Article

# A Printed Triangular Monopole With Wideband Circular Polarization

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## Abstract

A printed triangular monopole antenna with wideband circular polarization is presented. The wideband circular polarization is achieved by asymmetrical excitation of a triangular ground plane and planar triangular monopole. The combined radiation provides a wide axial-ratio bandwidth spanning from 1.42 to 2.7 GHz (62%). A parametric study of key geometric parameters is given for clear understanding of the radiation mechanism.

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... A linearly polarised (LP) receiver antenna can receive a CP wave regardless of its orientation [9]. Moreover, circular polarisation could minimise multipath losses [10][11][12]. ...
... Printed antennas are receiving considerable attention with regard to their use in indoor environments because of their compact size, low profile, simple design, uncomplicated design and fabrication and low production cost [10,[16][17][18], in addition to their capabilities of generating CP waves whilst retaining a compact antenna size [19,20] and providing bidirectional radiation patterns, RHCP and LHCP; these properties are essential for antennas which are used in indoor environments [21]. However, these types of antennas suffer from the difficult trade-off between the achieved IBW and axial ratio bandwidth (ARBW) and their size [22][23][24][25][26]. ...
... The pure polarisations of planar and nonplanar monopole and dipole antennas are linear [10,[49][50][51]. Therefore, applicable techniques are needed to design indoor antennas with a circular polarisation property. ...
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Article
With the rapid changes in wireless communication systems, indoor wireless communication (IWC) technology has undergone tremendous development. Antennas are crucial components of IWC systems that transmit and receive signals within indoor environments. Thus, the development of indoor technology is highly dependent on the development of indoor antennas. However, indoor environments with limited space require the fewest indoor antenna units and the smallest indoor antenna sizes possible. Hence, indoor antennas with compact size and broad applications have become widely preferred. In an IWC system, circularly polarised (CP) antennas are generally important, especially in dense indoor environments, because compared with linearly polarised (LP) antennas, CP antennas reduce polarisation mismatch and multipath losses. This paper combs through the existing studies related to three-dimensional (3D) geometry (nonplanar) or waveguide indoor antennas and the two common approaches to two-dimensional (2D) geometry (planar) indoor antennas, namely, broadband CP printed monopole antennas (BCPPMAs) and broadband CP printed slot antennas (BCPPSAs). The advantages, disadvantages and limitations of previous works are highlighted as well. These research works are summarised, compared and analysed to understand the recent specifications of BCPPMAs and BCPPSAs to generate the most appropriate design structure suitable for current IWC systems.
... In this case, a wideband CP was obtained by applying perturbations to the rectangular slot [12] and exciting the even and odd modes of the CPW with a 90°p hase difference [13]. In references [14,15], printed rectangular and triangular monopoles were shown to achieve an AR bandwidth of more than 50%. Here, circular polarization was obtained via an asymmetric antenna design. ...
... Here, circular polarization was obtained via an asymmetric antenna design. While the feed networks of the antennas presented in references [12][13][14][15] were simple, the radiation patterns were omnidirectional, the antenna gains were small, and the beamwidths of the circular polarization were insufficient in some frequency ranges. To enhance the gain of these antennas, the researchers in references [16,17] proposed employing a frequency selective surface (FSS) as a reflector; however, this necessitated an increase in antenna dimensions. ...
... The performance of the proposed CP antenna is compared with that of other recent works in Table 1. As shown, the proposed antenna had a wider AR bandwidth than that of the antennas proposed in [6][7][8][9][10] and a narrower impedance bandwidth than the antennas in references [10,12,13,15], although the proposed antenna exhibited a higher peak gain. When compared to the antennas in references [16,17], the proposed antenna had a smaller impedance bandwidth, a comparable AR bandwidth and peak gain, and a significantly smaller size. ...
Article
In this paper, a wideband, circularly polarized patch antenna is proposed that leverages the unidirectional resonant modes of a circular patch mounted on top of a grounded dielectric‐ferrite substrate. The proposed antenna is fed via the proximity coupling method and several parasitically coupled patches are placed on a dielectric superstrate to enhance the impedance bandwidth of the antenna. The resonant modes of the structure rotate only in the clockwise or counter clockwise directions. In the frequency range where the effective permeability of the ferrite layer is negative, the resonance frequencies of these modes differ significantly, which produces a large axial ratio (AR) bandwidth. For the proposed antenna, the numerical results show the 10 dB impedance bandwidth to be around 44% and the 3 dB axial ratio bandwidth to be higher than 64%.
... In the available literature, several design techniques have been used to achieve wideband circular-polarisation (CP) in printed microstrip antennas [4][5][6][7][8][9][10][11]. An asymmetric excitation of a planar triangular monopole and triangular ground plane has resulted into a wideband circular polarisation with axial ratio bandwidth (ARBW) 62% [5]. ...
... In the available literature, several design techniques have been used to achieve wideband circular-polarisation (CP) in printed microstrip antennas [4][5][6][7][8][9][10][11]. An asymmetric excitation of a planar triangular monopole and triangular ground plane has resulted into a wideband circular polarisation with axial ratio bandwidth (ARBW) 62% [5]. A broadband CP monopole antenna was achieved with chifre-shaped monopole radiator in association with its asymmetric feed [6]. ...
... Here the six prototypes of proposed CP antenna are depicted in Fig. 2 (Ant. [1][2][3][4][5][6] and their performances are explained in details. ...
Article
A new geometry of wideband circularly polarized antenna with an asymmetric meandered-shaped monopole is proposed in this communication. The wideband characteristics of the antenna are accomplished by the two asymmetric meandered-shaped perpendicular arms of monopole and defected ground structure having slanting edge. The proposed prototype offers good performance in terms of impedance-bandwidth (close to 102.04% in the frequency range 2.4—7.4 GHz) and the 3-dB axial-ratio bandwidth (close to 37.5% in the frequency range 4.9—6.9 GHz). The realized impedance and axial-ratio bandwidths cover the WLAN/Wi-MAX bands and Wi-Fi band (5.5GHz).
... Therefore, the polarization of radiation patterns must be convenient for indoor antennas, especially if the indoor antennas use wideband or broadband omnidirectional radiation. While conventional monopole and dipole antennas are linear polarized [9], [10],The recent research has tried to reject linear polarization antennas. This has motivated the researcher to focus on circular polarization (CP) antennas due to their many advantages over linear polarization (LP) as follows: (a) CP minimizes the mismatching between the transmitter and the receiver antennas, so that the antenna can receive radiation waves from various directions [3], [11]. ...
... (b) CP enhances the antennas to cover a large area with stable gain and good signal quality [12], [13]. (c) CP provides the antennas a strong immunity to multipath losses and Faraday rotation, causing a signal reflection fromground surface and building walls [9], [14]. (d) CP antennas have an important feature for being used as indoor antennas, namely the capability to penetrate without any losses [15]. ...
... It is a new shape for dipole antenna (trident operations for WLAN coverage bandwidth in each band cylinder shape with applied fo omnidirectional radiation pattern with CP, and to enhance AR sufficient bandwidth to cover all the different frequency ranges with a single antenna alleviate the environmental pollution inside buildings. 9 (a). G NTENNA It presents unidirectional radiation been applied to widen the bandwidth and compact size. ...
Article
This paper presents a review of several antennas topologies applied for indoor applications. Few requirements are desired for those antennas fo r their suitability for indoor applications. Such as antenna size, antenna profile, simple structure, omnidirectional radiations, polarization, and sufficient bandwidth to cover the most wireless communications bands, including GSM, LTE, WLAN ,WiFi and WiMAX. This paper focuses on minimizing the number of antennas needed to cover all these frequencies while offering convenient polarization to mitigate the fading problems and multipath effects losses. To meet these requirements, a monopole antenna with circular polarization is suggested. In addition, various topologies of monopole and dipole antennas are discussed in this paper in terms of their advantages and challenges. Moreover, this review is helpful to understand the current developments in indoor antenna topologies and it proposes a new antenna with a sufficient design for modern indoor applications.
... and cost, broadband CP antenna has become a very hot research topic in antenna design field. Recently, there are some basic types [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] to design broadband CP antennas, such as printed slot antenna [3][4][5][6][7][8], printed monopole antenna [9][10][11][12][13], combined slot-monopole antenna [14][15], and printed dipole antenna [16][17][18]. Compared with traditional microstrip CP antennas, all the CP antennas [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have wider impedance bandwidth and 3-dB AR bandwidth. ...
... and cost, broadband CP antenna has become a very hot research topic in antenna design field. Recently, there are some basic types [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] to design broadband CP antennas, such as printed slot antenna [3][4][5][6][7][8], printed monopole antenna [9][10][11][12][13], combined slot-monopole antenna [14][15], and printed dipole antenna [16][17][18]. Compared with traditional microstrip CP antennas, all the CP antennas [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have wider impedance bandwidth and 3-dB AR bandwidth. ...
... Recently, there are some basic types [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] to design broadband CP antennas, such as printed slot antenna [3][4][5][6][7][8], printed monopole antenna [9][10][11][12][13], combined slot-monopole antenna [14][15], and printed dipole antenna [16][17][18]. Compared with traditional microstrip CP antennas, all the CP antennas [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have wider impedance bandwidth and 3-dB AR bandwidth. Thus, these new types of CP antenna have a great impact on application and research prospect in many broadband communication systems. ...
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Article
In this paper, a novel wideband circularly polarized (CP) slot antenna and its array are presented. The antenna element consists of a C-shaped slot and a 50-Ω microstrip-fed port to achieve left-hand circular polarization (LHCP). Both the impedance bandwidth (IBW) and the 3-dB axial ratio bandwidth (ARBW) are greatly broadened by off-center microstrip-fed sword-shaped structure. A 2×2 array prototype based on the proposed CP element is also designed. Sequential rotation microstrip-feeding structure is used to excite four antennas and to realize good symmetric unidirectional radiation. To verify this design, both the CP antenna element and 2×2 array are fabricated and measured. The measured results of the antenna element exhibit an IBW of 132.0% (0.85~4.15 GHz), an ARBW of 95.7% (1.20~3.40 GHz). The Measured ARBW and IBW of the 2×2 antenna array is about 108.3% (1.10~3.70 GHz) and 100.0% (1.15~3.45 GHz), respectively. And the measured peak gain of the antenna array reaches 13.4 dBic. The proposed antenna is very suitable for CP applications in L/S bands. CCBY
... In this work, a broad-band close to 6.3 GHz pirating between 2.17 and 8.47 GHz in addition to dual CP-band of 150 MHz at lower center frequency 2.5 GHz and 900 MHz at upper center frequency 3.4 GHz have been achieved. The CP can also be observed by exciting a triangular ground plane and planar triangular monopole in asymmetric manner [3]. A compact circularly polarized (CP) slot antenna fed by a microstrip feed line was achieved by protruding a horizontal stub from the ground plane towards the center of the wide slot (WS) and then feeding the WS with a microstrip feed line positioned to the side of the WS, underneath the protruded stub [4]. ...
... In the available literature, most of CP antennas are complex in design and have relatively low 3-dB axial-ratio bandwidth (ARBW). Table 1 displays a comparative performance of the proposed design with other antennas reported above [2][3][4][5][6][7][8][9][10][11][12][13][14]. ...
... The longer (vertical) arm, > L l 1 0 becomes capacitive and radiates waves that are in phase advance while the shorter (horizontal) arm, < L l 2 0 becomes inductive resulting in waves radiated with a relative phase lag [1]. With suitable adjustment and optimization of the slanting edge ground plane shape and size [3], and length of orthogonal arms L1 and L2, the required 90°F phase-shift between the two unequal antenna arms are tuned. When the shorter arm length is around 52% than that of the longer arm, the ARBW is below 3 dB for resonant frequency 5.3 GHz. ...
Article
This communication describes a novel design of circularly-polarized (CP) monopole antenna for dual-band performance. The proposed design offers an impedance bandwidth (IBW) of 3.7 GHz in the frequency range 2.9–6.6 GHz in the lower band and 1 GHz (7.7–8.7 GHz) in the upper band. Proposed antenna has a wide CP (3 dB axial-ratio) bandwidth of 2.42 GHz (46.6%) in lower band (4.08–6.5 GHz) and 300 MHz in upper frequency band (8.1–8.4 GHz). The CP bandwidth is achieved through dual orthogonal arms and slanting edge defected ground structure (DGS). Proposed antenna is suitable for the C-Band wireless applications including WLAN, Wi-MAX communication systems.
... However, these antennas have not only the narrow overlapped AR bandwidth but also the large volume. A triangular monopole (AR and impedance bandwidths of 62%) [13], an L-shaped microstrip feed with the hook-shaped ground methodology (AR bandwidth of 63.61% and impedance bandwidth of 56%) [14], and an L-shaped CPW-fed CP monopole antenna (AR bandwidth of 98% and impedance bandwidths 103%) [15] have been investigated to have the wide overlapped impedance and 3 dB AR bandwidths. However, the AR bandwidth still needs to be improved for high-speed internet. ...
... Table 1 encapsulates the performance comparison between the proposed CP antenna and prevailing CP antennas in terms of −10 dB impedance bandwidth, antenna size, overlapped CP bandwidth and peak gain. From Table 1 it can be decided that the proposed antenna has an extremely wide AR bandwidth, miniaturized size with simple design and high gain as compared to the antennas cited in [7][8][9][10][11][12][13][14][15]. ...
Article
In this report, a miniaturized low profile circularly polarized (CP) monopole antenna with broad 3 dB axial ratio (AR) bandwidth is investigated. The proposed antenna comprises an equilateral triangular monopole radiator, an inverted L-shaped element (ILSE) protruded from the finite ground plane to perturb the current distribution on the finite ground plane and an inverted L-shaped strip (ILSS). The CP radiation characteristics can be achieved by protruding an ILSE from the finite ground plane and connecting ILSS with the triangular patch. The proposed CP antenna has a −10 dB impedance bandwidth along with the 3 dB AR bandwidth of 127.3% in the frequency band of 2−9 GHz. The antenna occupies the overall footprint of 20×25×0.8mm3 and is ideally propitious for broadband wireless communication systems which permit users to access high-speed internet. Furthermore, the proposed antenna has stable bidirectional radiation properties with a measured peak gain of 6.3 dBi.
... Microstrip antennas usually have a large size but narrow CP bandwidth. However, in recent years, many techniques have been proposed to achieve wide CP bandwidth [2][3][4][5]. By introducing asymmetric triangular ground plane, a wide CP performance can be achieved as in [2]. ...
... However, in recent years, many techniques have been proposed to achieve wide CP bandwidth [2][3][4][5]. By introducing asymmetric triangular ground plane, a wide CP performance can be achieved as in [2]. A quad-band CP antenna with narrower CP bandwidth is presented in [3]. ...
... Besides, these type of antennas suffers narrow bandwidth. To minimize the above drawbacks, various recently reported CPW (Coplanar Waveguide) antennas, monopole antennas, reactive impedance surface based UWB (Ultra Wideband) antennas and different shape slot antennas were studied [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. To enhance the performance of the small antenna especially gain and impedance bandwidth, several researchers were used reactive impedance surfaced metamaterial [17]. ...
... An asymmetrical Y-shaped feeding line is used to produce the CP radiation for X band applications and a through via in series with an inductive strip is employed to achieve an impedance bandwidth of 31.4% [23]. A wideband CP printed triangular monopole antenna is also proposed in [24]. By asymmetrical excitation of a trilateral ground plane and a planar triangular wideband circular polarization is achieved, which is covering 1.42 to 2.7 GHz (62%). ...
Full-text available
Article
A simple, compact sickle-shaped printed antenna with a slotted ground plane is designed and developed for broadband circularly polarized (CP) radiation. The sickle-shaped radiator with a tapered feed line and circular slotted square ground plane are utilized to realize the wideband CP radiation feature. With optimized dimensions of 0.29λ × 0.29λ × 0.012λ at 2.22 GHz frequency for the realized antenna parameters, the measured results display that the antenna has a 10 dB impedance bandwidth of 7.70 GHz (126.85%; 2.22–9.92 GHz) and a 3 dB axial ratio (AR) bandwidth of 2.64 GHz (73.33%; 2.28–4.92 GHz). The measurement agrees well with simulation, which proves an excellent circularly polarized property. For verification, the mechanism of band improvement and circular polarization are presented, and the parametric study is carried out. Since, the proposed antenna is a simple design structure with broad impedance and AR bandwidth, which is a desirable feature as a candidate for various wireless communication systems. Because of the easy printed structure and scaling the dimension with broadband CP characteristics, the realized antenna does incorporate in a number of CP wireless communication applications.
... Recently, the planar printed antenna has been used to design single-broadband CP antennas [11]. There exist some basic antenna types [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] to design broadband planar printed CP antennas such as printed slot antennas [12-17], monopole antennas [18-22], slot-monopole antennas [23, 24] and dipole antennas [25-27]. Compared to traditional microstrip CP antennas [4-6], all the planar printed single-broadband CP antennas [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] have both wider impedance and 3 dB AR bandwidths. ...
... There exist some basic antenna types [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] to design broadband planar printed CP antennas such as printed slot antennas [12-17], monopole antennas [18-22], slot-monopole antennas [23, 24] and dipole antennas [25-27]. Compared to traditional microstrip CP antennas [4-6], all the planar printed single-broadband CP antennas [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] have both wider impedance and 3 dB AR bandwidths. Planar printed antenna also has been used to design dual-band CP antennas [28]. ...
Full-text available
Article
A dual-wideband dual-sense circularly polarised (CP) planar slot antenna with a simple structure is presented and studied in this study. By etching a simple spiral slot on the planar ground, adopting an L-shaped strip as the radiator, and employing smooth transition structure, the dual-wideband impedance bandwidths (IBWs) and dual-wideband 3 dB axial-ratio bandwidths (ARBWs) of the proposed CP antenna can be easily realised. The measured 10 dB return loss IBWs is 111.1% (0.88-3.08 GHz) for the lower band [left-hand CP (LHCP)] and 42.1% (3.64-5.58 GHz) for the upper band [right-hand CP (RHCP)]. The measured 3-dB ARBWs is 92.9 and 39.4%, with respect to 1.83 GHz (LHCP) and 4.6 GHz (RHCP), respectively. The radiation patterns of this antenna are good within both two CP bands. This antenna is very suitable for multi-band communication systems for its dual-wideband CP performance.
... By using broadband CP antennas, not only the multipath effects can be mitigated, but also the complexity inherent in the multiservice wireless systems can be reduced. In recent years, many broadband CP antennas have been proposed [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Among them, wide apertures with single feed structure have been widely studied, owing to their features such as wide impedance bandwidth, low cost low profile, and easy fabrication. ...
... The formula for TE 11 mode is not changed here, which is mainly because compared with the TE 11 mode wavelength, the width of the slots Ws is relatively small, thus has little influence on the TE 11 mode. Based on the mathematical interpretation, a physical explanation can be concluded that with the perturbation slots, the current path of TE 21 and TE 31 modes can be extended while having little influence on the behavior of TE 11 . Under this condition, the resonance frequencies of TE 21 and TE 31 modes can be reduced, while keeping TE 11 resonance frequency almost stable. ...
... To ensure simplicity and compactness, a single, electromagnetically coupled feed technique is chosen based on its proven capability in exciting CP behaviour [19][20]. Researchers in [22][23] demonstrated that wide bandwidths of 62 % (impedance) and 51.4 % (AR) were achievable by a printed monopole microstrip antenna. However, the gains produced from these proposed structures are relatively low, making them incompatible for ambient energy harvesting. ...
... Finally, the proposed antenna is compared with other single-feed CP antennas from literature, as illustrated in Table 4. In both [22] and [23], the researchers successfully attained a wideband of 62 % and 51.4 % AR, which is about two to three times of the proposed antenna. However, these antennas exhibited a low gain of around 2 dBic, which makes them unsuitable for energy harvesting application. ...
Full-text available
Article
A novel of wideband circular polarization (CP) antenna with high gain that is suitable to harvest energy is proposed. In this article, our objective is to design an antenna that is capable of fully harvesting ambient RF energy. A survey on the feasibility of scavenging for RF energy was conducted through power density measurement in an urban area. Using the results, a CP antenna was designed to cover the frequency band from the largest RF contributors, ranging from 1.73 to 2.61 GHz in GSM1800, UMTS, WiMAX and the unlicensed industrial, scientific, and medical (ISM) bands. Hence, a simple single feed electromagnetic (EM) coupled circularly polarized antenna with high gain is presented. The wideband CP is achieved by implementing EM coupled feed with a defected ground plane structure. Experimental results showed the antenna achieved an axial ratio bandwidth of 25% with respect to 2.08 GHz center frequency. Furthermore, the antenna exhibits broad impedance bandwidth of 32.77% with the measured peak gain is 8.7 dBic at 2.05 GHz. The proposed antenna structure is simple and low cost with a size of 0.462 λo and wide 22.1% axial ratio bandwidth.
... e authors in [34,37] demonstrated the concept of an electromagnetic coupling using a single feed line to maintain simple antenna geometry. A tilted rectangular and triangular wideband monopole printed antennae are exploited by the authors in [38,39]. e designs reported a FBW of 51.40% and 62.00%, respectively. ...
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Article
The design of a wideband circular-slot antenna for RF signal harvesting is reported in this work. The proposed design frequency range accommodates the leading contributors to the available RF signals accessible by the RFEH node. These widely utilized frequency bands comprise GSM1800, UMTS2100, Wi-Fi2.450, and LTE2600. The antenna geometry comprises circular-ring radiating component filled with two orbital circular and rectangular slots. At the bottom plane, a pair of rectangular and semirectangular-circle slits are integrated. The antenna presented is designed on a double layer of 1.6 mm high FR-4 substrate. The source antenna achieved a simulated and measured impedance bandwidth (BW) of 1.510 and 1.590 GHz, amounting to 68% and 73% fractional BW (FBW), covering -10 dB reflection coefficient (|S11|) between 1.640 to 3.150 GHz and 1.550 to 3.140 GHz, in that order. The wideband circular-slot source antenna realized a maximum measured gain of 1.88, 2.13, 2.81, 3.22, and 4.32 dBi for 1.800, 2.100, 2.450, 2.650, and 3.20 GHz, respectively. The proposed design dimension on the printed board is 0.61 λ g × 0.70 λ g . The improved antenna gain is obtained from a circular parasitic patch coupled to the defected ground structure (DGS) for better RF energy harvesting in an ambient environment.
... It can mitigate polarization mismatch [27]- [28]. It can be used in radar, RFID, satellite communication, sensor systems, and global navigation system [29]- [30]. ...
... An RFEH source antenna with a high gain can capture more signals from the environment, because the antenna's gain is proportional to its electrical aperture. Antennae with a high gain are needed when the direction of incidence of the incoming RF signal is predictable [116][117][118][119][120][121][122]. In addition to high antenna gain, the antenna's omnidirectional pattern ensures better reception of incoming RF signals, especially in an ambient environment. ...
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Article
The RFEH design challenges can be broadly classified into overall radio frequency direct current (RF-to-DC) power conversion efficiency (PCE), form factor, operational bandwidth (BW), and compactness. A detailed overview of the essential components of an RFEH system is presented in this paper. Various design approaches have been proposed for the realization of compact RFEH circuits that contribute immensely to mm-wave rectenna design. Effective mechanisms for configuring the rectenna modules based on the recommended spectrums for the RFEH system were also outlined. This study featured a conceptual viewpoint on design tradeoffs, which were accompanied by profound EH solutions perspectives for wireless power communications. The work covers some challenges attributed to 5G EH in mm-wave rectenna: from a controlled source of communication signals to distributed ambient EH and system level design. Conversely, the primary targets of this work are to: (I) examine a wide range of ambient RF sources and their performance with various antennae and RF-rectifier layouts; (II) propose unique rectenna design techniques suitable for current trends in wireless technology; (III) explore numerous approaches for enhancing the rectenna or RF-rectifier efficiency in a low-power ambient environment; and (IV) present the findings of a comprehensive review of the exemplary research that has been investigated. These are aimed toward addressing the autonomous system’s energy challenges. Therefore, with the careful management of the reported designs, the rectenna systems described in this study would influence the upcoming advancement of the low-power RFEH module.
... The asymmetrically-fed rectangular patch and the modified ground plane in [5] produce a bandwidth of 51.4%. Panahi et al. [6] propose a CP antenna using the triangular patch and the triangular ground plane with 58.7% bandwidth. The printed monopole antenna with a moon shape and the optimized ground plane is designed in [7] and a bandwidth of 49% is achieved. ...
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Article
This paper presents the design of a wideband circularly-polarized printed monopole antenna with a rhomboid shape. The rhomboid-shaped patch is fed by a microstrip line offset from the center to generate circular polarization (CP). The ground plane configuration is optimized for wide bandwidth operation. Bandwidth (satisfying both 10-dB return loss and 3-dB axial ratio) of 76% (1.92 - 4.27 GHz) is achieved in this research. The size of the proposed antenna is 0.386 2 0 l (55×66 mm2) where λ0 is the free space wavelength which corresponds to the center frequency of the bandwidth. The antenna has a fractional bandwidth-size ratio (BW/size) of 1.97 which is higher than most CP monopole antennas in the literature. This antenna is suitable for Wi-Fi, WiMAX, and other wireless applications which outperform using circular polarization.
... Despite the low AR bandwidth of traditional microstrip antennas, relatively few articles have been published in the literature about wide AR bandwidth. Approaches noted in those works have included exciting a triangular or rectangular monopole antenna using asymmetry feeding [2][3][4] and introducing a parasitic element in the antenna structure with a grounded stub or grounded slot [5,6]. Although this printed monopole antenna design method can offer an optimum AR bandwidth within the impedance bandwidth (IBW), in the recent past, the wide slot antenna has provided a palpable broadband CP (BBCP) antenna design due to its low Q-value. ...
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Article
Abstract A compact broadband circularly polarized square‐slot antenna based on an offset‐fed inverted‐L‐shaped microstrip feed line is proposed. A rectangular slot beneath the feed line and an inverted‐L‐shaped grounded strip on the left bottom corner of the wide square slot produce dual‐wideband circular polarization (CP) coverage in a compact size. Meander lines with a square slot loaded at the right bottom corner of the ground plane result in broadband CP through overlapping of the dual‐wideband axial ratio (AR) bandwidths. The magnitude and phase differences between two field components can be controlled effectively with proper tuning of the square slot dimensions (4.5 × 4.5 mm2), which is helpful for broadening AR bandwidth over the C‐band by minimizing AR values (≤3 dB). The overall dimensions of the prototype are only 26 × 26 × 1.6 mm3. The antenna prototype has been validated experimentally. The measured results indicate an impedance bandwidth of 104% (3.56–11.22 GHz) and a 3 dB AR bandwidth of 76% (3.90–8.72 GHz). A peak gain of 3.4–4.42 dBi is achieved within the AR bandwidth. The proposed antenna is suitable for CP applications in the C‐band.
... They are simple, low cost, omni-directional, and characterized with wide operational bandwidth. The feeding of printed monopole antennas has been suggested in different configurations including microstrip and coplanar waveguide (CPW), where they aim for optimum impedance matching and radiation pattern properties over the entire antenna bandwidth [2][3][4][5][6][7][8][9]. Monopole antenna can be adapted for multi-band functionalities by incorporating it with other resonators. ...
Article
An inspired metamaterial-based highly efficient monopole antenna displaying wide-/dualband resonances along with self-filtering properties is presented. The monopole has high out-of-band suppression characteristics that lead to very close to 0 dB band-stop between the antenna dual resonant bands. The antenna operates at the two WLAN services of 2.65–3.25 and 5–7 GHz with stopband with total reflection at 4.5 GHz. The designed filtering characteristics are based on current coupling for the dual-band functions and current neutralization for the stopband function. Moreover, the proposed antenna has a very high radiation efficiency of 97 and 99% at 3 and 6 GHz, respectively. Furthermore, the proposed antenna exhibits an omni-directional radiation pattern with coplanar waveguide feed for simple integration with passive/active devices. Moreover, the antenna properties are achieved with a compact antenna size (30 × 30 mm2). With all presented results, the proposed antenna is very competitive over recent relevant antennas. In addition, a very good agreement between theoretical, full-wave simulations and measurements is achieved.
... A chifre-shaped monopole rad iator [3] with asymmetrical feed is offered to have a wide axial ratio of 41.6%. A wide AR bandwidth is attained by using an asymmetrical excitation of a triangular monopole [4] with a triangular ground, where it is shown that ground plane plays a very significant role in generating the circu lar polarization. An asymmetrical ground with L-shaped strips [5] are utilized to generate CP feature having wide axial ratio bandwidth. ...
... For recent trade-off analysis, two terms are introduced in the last two columns. Column (6) shows the evaluated ratio between the achieved differential ARBW according to size (AR/λ o 2 ). Column (7) presents the overlapping (OL) ratio achieved between ARBW and IBW (ARBW/ IBW). ...
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Article
In this communication, a broadband circularly polarized (CP) monopole antenna with coplanar waveguide (CPW) feeding is proposed. It consists of a modified rectangular monopole, an asymmetric ground plane, a two‐linked inverted L‐shaped strips on the left CPW ground, and two rectangular horizontal slots in asymmetric CPW ground plane. The overall dimension is only 0.47λo × 0.47λo. The antenna prototype has been fabricated. The measured results indicate that a broad −10 dB impedance bandwidth (IBW) of 107.5% (4.3 GHz, 1.85‐6.15 GHz) and a broad 3 dB axial ratio ARBW of 104.3% (4 GHz, 1.855‐5.9 GHz) can be achieved; the average realized gain is 2.3 dBi for the entire CP band. The proposed antenna is an attractive candidate for several wireless communication systems.
... And the variation of matching and axial ratio with the variation of dimensions of the ground and monopole is well explained. Wideband circular polarization with more than 60% axial ration bandwidth is achieved by asymmetrical excitation of a triangular ground plane and planar triangular monopole in [9]. A parametric study of key geometric parameters is given for clear understanding of the radiation mechanism. ...
Conference Paper
A Simultaneously Dual Circularly Polarized planar monopole antenna for broad band wireless applications is presented. The antenna is compact and occupies less space (60mm×60mm×1.6mm) and suitable for low cost PCB fabrication techniques. The orthogonal circular polarizations on the opposite sides of the antenna are achieved essentially by placing the two perpendicular monopoles of almost same dimensions along with strategically shaped ground. The role of the dimensions of the ground plane, monopole and asymmetry in producing orthogonal fields is explained. The simulated impedance bandwidth is 77% and axial ratio bandwidth of (AR<3 dB) 20% is achieved. The antenna could possibly be useful in the severe multipath wireless environments. The common bandwidth of 20% is achieved for circular polarization.
... Shen et al. introduced an asymmetrical Y-shaped feeding line patch antenna to generate CP radiation for X-band applications, and a through via that is in series with an inductive strip was employed to achieve the impedance bandwidth of 31.4% in which the AR is less than 2 dB [16]. More recently, a wideband circular polarized printed triangular monopole antenna was proposed [17]. An asymmetrical excitation of a trilateral ground plane and a planar triangular monopole wideband produces circular polarization. ...
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Article
In this paper, a novel compact circularly polarized (CP) monopole wideband printed patch antenna is proposed. The antenna consists of a hook-shaped branch connected at the partial rectangular ground plane and reversed unequal arm with an L-shaped microstrip-feed which helps the antenna achieve wideband circular polarization property. The measured results display that the proposed compact (44×44×1.6 mm3) antenna acquires 3.12 GHz (56%, 2.25–4.0 GHz) at the 10 -dB impedance bandwidth, and the axial ratio (AR) bandwidth at 3-dB is 3.48 GHz (63.61%, 2.38–4.60 GHz). A parametric study of different design parameters and measured and simulated results of the various characteristics of the designed antenna is presented to verify the performance of the radiation mechanism. Finally, by scaling only, the dimensions of the proposed antenna without changing another parameter, a wide impedance and AR bandwidth are achieved. On account of the simple planar structure and scaling dimension with broadband CP property, the proposed antenna does apply in a variety of wireless communication systems like ISM, WiMAX, WLAN, satellite communications, cordless telephones, weather radar systems and lower frequency bands CP type applications.
... And the variation of matching and axial ratio with the variation of dimensions of the ground and monopole is well explained. Wide band circular polarization with more than 60% axial ration bandwidth is achieved by asymmetrical excitation of a triangular ground plane and planar triangular monopole in [8]. A parametric study of key geometric parameters is given for clear understanding of the radiation mechanism. ...
... In [3], two orthogonal arms with unequal length are utilized to provide a quadrature phase difference for CP generation in place of using external coupler network. For those without orthogonal geometry, another effective solution to achieve CP radiation is to employ asymmetrical feeding [4,5] and improved ground plane [6,7]. These works have one common characteristic that they try to break the balanced surface current distribution on radiators or ground plane by perturbations, such as embedded stubs [8] and slits [9], so as to generate two orthogonal linearly components with equal amplitude and quadrature phase for CP radiation. ...
Article
novel design approach to circularly polarized (CP) conical RFID reader antenna is presented in this paper. Firstly, operational principle of the proposed antenna is revealed by exploring the distribution of natural boundary conditions. It is demonstrated that due to the introduction of a shorting pin, the proposed antenna is dominated by two resonate modes, i.e., the monopole mode and loop mode, as the symmetrical property of conventional planar conical antenna is disturbed. As a result, the respective natural boundary conditions from these two modes will be sequentially excited with an interval of one-quarter of temporal period, thus the surface current becomes rotated and a CP wave is radiated. Prototypes with CP bidirectional and unidirectional radiation centered at 2.4 GHz are then fabricated and tested. It is shown that they can achieve a 3-dB axial ratio (AR) bandwidth about 5.38% and 2.84% in +y direction, respectively, which is further demonstrated that the design approach can be employed to effectively generate CP radiation without the use of orthogonal structures, modified ground plane as well as extra polarizer.
... In [16], by cutting one of the CPW ground-plane, CP performance can be achieved. A planar triangular monopole antenna in [17] with CP performance is studied. However, these antennas can hardly radiate CP waves for dual-band operation. ...
Article
A novel planar monopole antenna with dual-band circularly polarisation (CP) is presented here. The antenna consists of a modified L-shaped monopole, an inverted-L strip, and a modified ground. The utilisation of the modified L-shaped monopole not only generates dual-band operation, but also excites CP radiation in the lower band. In order to achieve CP in the upper band, a parasitic inverted-L strip is added on the top plane of the substrate and a modified ground is designed. The proposed antenna has been fabricated and tested, the measured -10 dB reflection coefficient bandwidths are 370 MHz (2.38-2.85 GHz) in the lower band and 2330 MHz (4.05-6.38 GHz) in the upper band. The measured corresponding 3 dB axial ratio (AR) bandwidths are 610 MHz (2.39-3 GHz) and 850 MHz (5.15-6 GHz), respectively. The overlapped -10 dB reflection coefficient and AR bandwidths can totally cover the WLAN bands, Wi-Fi bands, Bluetooth band, and partly cover the WiMAX bands. The proposed antenna owns bidirectional radiation characteristic and reasonable gain at both the lower band and the upper band.
... Apart from these techniques, the CP bandwidth can also be improved using asymmetrically fed monopole antennas. [9][10][11][12] In the recent literature, an L-shaped radiator with broadband and unidirectional CP radiation was reported for array applications 13 and a C-shaped radiator with a modified ground plane in Ref. [14] achieves a 3-dB AR-BW of 104.7%. ...
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Article
A novel approach in the design of broadband circularly polarized antennas is presented in this article. The design uses a simple monopole structure with a triangular tapered feed. Right-/left-hand circular polarization (CP) is achieved by protruding L-shaped strip and inverted L-shaped strip along the left/right radiating edge of the monopole. It is proposed that the 3-dB axial ratio bandwidth (AR-BW) can be enhanced when the length of these strips is equal to λg/4 at the center frequency of their respective CP bands. This principle is verified by fabricating the prototype on 1 mm thick FR4 substrate occupying a compact area of 0.19 λ0 × 0.19 λ0. From the measurement results, it is observed that the overlapped bandwidth (S11 ≤ −10 dB and AR ≤ 3 dB) of the antenna is 129.04% (1.38–6.4 GHz) which covers all the major WLAN bands including the WiMAX. The proposed antenna has bi-directional radiation characteristics with a broadside gain of 3.49 dBic in the CP band.
... Similarly, L-shaped and inverted L-shaped strips were also introduced to achieve broad CP bandwidth [9]. Besides, triangular- [10] or chifre-shaped [11] MAs were also proposed to obtain broad AR BW. ...
... Printed monopole antennas (PMA) are prominent candidate for broadband and ultra-wide band applications, having features of large impedance bandwidth and omnidirectional radiation patterns. Some of the simulation and experimental works on PMAs are available in the literature [1]- [5]. However, theoretical analysis of radiation characteristics of PMAs is not adequately dealt in the literature. ...
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Article
This paper reports a theoretical approach to analyze radiation pattern and gain of Printed Monopole antennas (PMA). Theoretical analysis of PMAs is performed by modeling PMA as an asymmetrical dipole antenna. The effect of patch and ground plane is considered separately then combined. The far field expressions for rectangular and circular PMAs are derived and verified with available experimental results from published works and High Frequency Structure Simulator (HFSS) simulated results. The analytical, simulated and available measured results are in close agreement. The theoretical gain for rectangular and circular monopole antennas are also computed and compared with HFSS simulation results.
... Several designs of small, low-cost, UWB antennas have been reported in the literature [10]. For example, a printed triangular monopole antenna with wideband circular polarization was presented in [11]. The wideband circular polarization was attained through asymmetrical excitation of a triangular ground plane. ...
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Conference Paper
Abstract—This paper presents a miniature planar UWB microstrip patch antenna for breast cancer detection. The antenna can be placed on the breast skin to detect any possible breast tumors. Both simulation results and experimental measurements show good agreement for the return loss of the fabricated antenna in the UWB range from 4.23GHz to 11.71GHz. The antenna gain was found to vary from 2.25dBi to 4.55dBi over the operating band with 96% average radiation efficiency. Simulation results also indicate that the current density inside the tumor is about eight times higher when the antenna is placed in direct contact with the breast, compared to when it is placed 5 cm or 15 cm off the breast. Hence, the sensitivity of developed antenna for detecting breast tumor increases when the fabricated antenna is in direct contact with the breast skin.
Article
The most important characterizing parameters which determine the antenna performance are axial ratio bandwidth, impedance bandwidth and gain of wireless systems. The improvement of these parameters are presented in the proposed antenna. Basically, the proposed design consists of an inverted L-shaped microstrip feed line and modified ground plane. The size of the antenna is 0.4 × 0.28 × 0.0128 λ0 (where λ0 be the free space wavelength at f r of 2.4 GHz). The designed antenna has been fabricated and the measured results of fabricated antenna are compared with the simulated results. It is found that the results are very good in agreement. Novelty of the research work is the improvement of axial ratio (less than 3 dB) bandwidth. As a result, the antenna is circularly polarized for a good amount of bandwidth which is desired in the modern communication system. Circularly polarized antenna is able to transmit and receive both vertically and horizontally polarized electromagnetic waves.
Article
This paper proposes an orthogonally positioned inverted triangular monopole antenna over a compact plane reflector with stable radiation pattern for octave band of frequencies. Two triangles are placed crossed and orthogonal to each other to obtain nearly uniform omni-direction radiation pattern. The antenna is placed over a square reflector exhibits 73% bandwidth at (4.5 GHz). The measured impedance bandwidth and radiation pattern of the antenna match well with Finite Element Method (FEM) and Method of Moments (MOM) analysis of the structure. The antenna is novel in its orthogonal design and the triangles fed differently with compact reflector. The designed octave band planar antenna (3.0–6.5 GHz) has applications in Wireless LAN and intelligent transportation systems (ITS). The compact antenna design with uniform radiation pattern is used as radiator inside a room and cabinets for RF isolation measurements.
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In this research work, a circularly polarized (CP) monopole antenna is designed for Ultra-Wideband (UWB) applications. The CP UWB antenna is be made up of a reformed ring patch and ground plane. The slots and stubs are inserted in the ground to achieve CP in the UWB antenna. This antenna attained an Axial Ratio Bandwidth (ARBW) of 5 GHz (4.0–9.0 GHz) that lies in the UWB frequency range that is from 3.1 to 10.6 GHz. The designed antenna has a radiation efficiency of around 80% for the complete UWB frequency range. The CP UWB antenna is designed and fabricated using the FR4 with a compact size of 32 × 30 × 1.6 mm3 and with a peak gain of 6.8 dBi. Tested results are in good resembles with simulated ones.
Article
A compact body-worn circular polarized textile monopole antenna for wearable applications is reported. The proposed antenna is fabricated on a jean fabric providing flexibility, lightweight, and easy integration into human clothes. The overall size of the proposed antenna is $25\times 30\times1.4$ mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Circular polarization (CP) is advantageous for on-body communication as it provides features, such as multipath immunity, suppressing interferences, and enables better link connectivity between the sensor nodes. The proposed antenna achieves the CP using an asymmetric stepped L-shaped ground plane and through the incorporation of a cross-shaped stub in the radiator. The single-fed octagonal strip monopole antenna provides good impedance matching over the entire ultrawide frequency range from 3.09 to 11 GHz. Simulation results are in good correlation with the measured results. The axial ratio bandwidth <3 dB is achieved in the frequency range of 3.4–10 GHz. Gain and efficiency obtained are about 2.3-4.4 dBi and 65%–82% at the said frequency range, respectively. Structural deformation is performed to analyze the flexibility of the proposed antenna. The simulated SAR values follow the FCC limit making it most suitable for wearable applications.
Chapter
This chapter discusses antennas used in Global Navigation Satellite System (GNSS) receivers of different types. It provides a generic overview of the propagation aspects relevant to GNSS signals and introduces key antenna parameters relevant to GNSS: axial ratio (AR) and antenna gain. It follows with overview of main antenna types used in GNSS receivers. Microstrip patch antennas and sequentially rotated arrays can offer very good performance at low cost, as they can be easily integrated into a printed circuit board (PCB) of the device. Quadrifilar helix antennas are more complex helical three-dimensional (3D) structures capable of good AR within very wide beam. However, they need to protrude from the device's PCB, making their integration more challenging. While current implementation of quadrifilar helix antennas are expensive due to manufacturing complexity, the ongoing research on antennas that use 3D printing might see their cost dropping in the near future. Omnidirectional antennas are discussed in the context of portable devices, where the orientation toward sky cannot be determined. The problem of antenna integration into compact devices is discussed: it should be noted an antenna will behave differently based on its environment, i.e., size and location on the ground plane, proximity to conducting objects, human/animal body, etc. All this aspects need to be considered when deciding on antenna design for the particular application. This chapter also discusses techniques for filtration of signals incoming from low angles above the horizon, which can be very problematic due to their depolarization. Such techniques often require increase in antenna volume.
Article
A novel wideband circularly polarized microstrip patch antenna (MPA) with multimode resonance is proposed in this letter. The TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2,0</sub> mode, the zeroth-order mode, and the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,0</sub> mode are excited by inserting the shorting pins underneath the driven patch and the parasitic patch. Therefore, a wide impedance bandwidth is achieved under triple-mode resonance. By sequentially rotating the triple-mode elements, a circularly polarized MPA is developed with a four-feed network. Additionally, four metallic side walls are employed to obtain desirable radiation performances. For demonstration, a prototype of the proposed antenna is fabricated and measured. The measured −10 dB impedance bandwidth is 96% (1.53–4.39 GHz) and 3 dB axial ratio bandwidth is 86% (1.74–4.36 GHz). Meanwhile, a low profile with the height of 0.037 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ( λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength in free space at the lowest operating frequency) is obtained. Such a wideband, low-profile, and circularly polarized antenna is very promising for modern wireless communication applications.
Article
Impedance bandwidth, multi-band, gain, and circular polarization (CP) are important characteristics of the microstrip antenna. In this paper, these characteristics have been highlighted by designing three different antenna structures. The proposed modified ground plane antenna consists of tilted G-shaped radiator (TGSR), which acts as a radiating element. The overall volume of the proposed antenna is 0.25λ0 × 0.2λ0 × 0.008λ0 (where λ0 is the free space wavelength of 1.5 GHz). The substrate used for fabricating the antennas is FR4. The Ant.I has multiband characteristics with four distinct frequency bands. However, Ant.II provides wide impedance bandwidth and also it has a single CP band, which covers the upper band of WLAN and WiMAX. Moreover, Ant.III (TGSR) exhibits two wide impedance bandwidths as well as two wide CP bands, supporting for WLAN, WiMAX, and X-band for satellite communication. The peak gains of Ant.I, Ant.II and Ant.III are about 5.5dBi, 6.6dBi, and 6.5dBic, respectively.
Article
A circularly polarized monopole antenna fed by coplanar waveguide is presented in this research. The antenna operates in wireless local area network and worldwide interoperability for microwave access bands. Circular polarization (CP) is achieved by using inverted L-shaped strips on both sides of a simple monopole and introducing asymmetries in the ground plane. The measured impedance bandwidth from 1.77 to 5.35 GHz while axial ratio bandwidth from 2.04 to 3.85 GHz are achieved. The proposed antenna has a gain of 0.6–2.8 dBi within the circular polarization band.
Article
This article presents the design and analysis of an ultrawideband (UWB) circularly polarized (CP) antenna element and its array. First, an UWB CP antenna element using circular-arc-shaped monopole (CASM) with asymmetric ground plane is proposed. Characteristic mode analysis (CMA) is used to investigate its CP operating mechanism, providing physical insights into different modes (mode currents and characteristic radiation fields) at various frequencies. The CMA results show that the asymmetric ground plane makes great contribution to produce CP radiation in the lower frequency band, while another upper CP band is generated by CASM. Thus, the overall 3 dB axial ratio bandwidth (ARBW) of the element can be significantly expanded. Furthermore, a $2 \times 2$ UWB CP array is designed based on this element. A gradient artificial magnetic conductor (GAMC) with a metal cone is adopted to realize both a low-profile ( $0.1 \times \lambda$ , where $\lambda$ is the air-free wavelength at lowest frequency) and the high-gain radiation for the first time. To validate this novel configuration, this array is fabricated and measured. The measured bandwidth ( $\vert S_{11} \vert < -10$ dB, AR < 3 dB) is approximately 92.3% (1.75–4.75 GHz). It also achieves a wide 3 dB gain bandwidth of 72.3%. Both the simulated and measured results demonstrate that this low-profile high-gain antenna array is promising for applications in wireless systems such as mobile satellite communication system.
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Aiming for ultra-wideband (UWB) indoor wireless access, three low-profile UWB circularly polarized slot antennas are proposed in this paper, all of which are made by a pair of curved tapered slots. The slots are miniaturized to allow a short direct microstrip feeding. The first antenna is a bidirectional antenna with a measured -10 dB impedance bandwidth of 110% (2.94 -10.06 GHz), and a 3 dB axial ratio (AR) bandwidth of 89% (3.19 -8.26 GHz). Its measured peak gain is 7.5 dBic and its size is 0.80 λImax λ0.80 λImax λ0.5 mm (λImax is the free-space wavelength at the lowest frequency, 3.19 GHz). Its performance is similar to that of a traditional spiral antenna, but it has a much simpler structure with a more complete ground plane, making it possible to integrate with other components (e.g. filter and amplifier) on the antenna body to reduce the overall size of the system. The second antenna is a directional antenna with a simple solid metal reflector placed 21 mm away from the radiator. This configuration increases the peak gain to 8.6 dBic, but reduces the impedance bandwidth to 52 only. The third one is a directional antenna with a meshed reflector. It has a maximum gain of 9.6 dBic, which is higher than that of the second antenna, while its -10 dB impedance bandwidth is 99 (3.37 – 9.94 GHz) and its 3 dB AR bandwidth is 84 (3.70 -9.07 GHz), which is similar to that of the first one. Also distance between the radiator and the reflector (antenna’fs height) is reduced to 9 mm only (0.111 λImax). The proposed antennas demonstrate high efficiency, simple and low profile structures, wide impedance and AR bandwidth, making them excellent candidates for in-door base station and UWB positioning systems.
Conference Paper
A wide-band circularly polarized modified square patch antenna with defected ground plane is proposed. The rectangular slot in feed of the patch has a major influence on impedance bandwidth. Further the triangular shaped slot in upper ground plane has improved the impedance bandwidth. The dual C-shaped slots in patch excite the orthogonal modes to realize circular polarization. The impedance-bandwidth of proposed design is 5.41 GHz ranging from 2.42—7.83 GHz in lower band of UWB and the axial-ratio (3-dB) bandwidth of 640 MHz ranging from 7.19—7.83 GHz. The peak realized gain of the design is 3.4 dBi in axial ratio band
Article
A novel 2×2 broadband circularly polarized low-profile monopole array antenna adopting the sequential rotation technique is presented and experimentally studied in this article. The array is very lightweight and is printed on the 0.2 mm flexible substrate. The basal antenna element of the 2×2 arrays is a printed curve-shaped monopole with good bandwidth and circular polarization property. The simulated and measured impedance bandwidth and axial ratio bandwidth are presented. Moreover, radiation patterns are also presented. The advantages of the proposed antenna include low-profile, light-weight, simple structure, and broad working bandwidth.
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In this communication, a novel compact and unidirectional circularly polarized (CP) antenna based on crossed printed tapered slot radiation elements is proposed with ultra-wideband (UWB) operation. The antenna consists of two crossed tapered slot radiation elements, a compact dual-feed network, and a dial-shaped parasitic metallic strip. The tapered slot element is applied and investigated for wideband coverage within a compact size. By using the proposed parasitic patches, an additional resonant point is formed to improve the operation bandwidth for the low band. To enhance the directivity in the low band, a dial-shaped parasitic metallic strip is loaded on the top substrate. With the proposed structure, a compact volume of 0.33 λ × 0.33 λ × 0.3 λ is obtained, where λ is the free-space wavelength at the lowest frequency 1.85 GHz. A prototype is fabricated and measured for validation. The overlapping bandwidth of the 10-dB impedance bandwidth and the 3-dB axial ratio (AR) bandwidth is 105.8% (1.85 GHz ~ 6 GHz). IEEE
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This paper presents a phased array consisting of 8 horizontally positioned planar log periodic dipole array antennas for use over the frequency range of 800 to 1,300 MHz. The array is dual use in that it can either scan in azimuth with a narrow beam or be forward looking with a null-filled broad beam. To achieve the broad beam, the 8-element array is divided into two 4-element subarrays. The main beam of each subarray is then pointed near the first null of the 8-element uniform array radiation pattern to "fill" the nulls. The results for the narrow beam configuration produce an azimuthal beamwidth of 15° with 15 dBi of gain, and the nullfilled configuration produces an increase in azimuthal beamwidth to 55° (40° increase) with a peak gain of 10 dBi (loss of 5 dB). Note that this paper only presents the antenna development and array testing but not any system hardware.
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We propose a wideband circularly polarized antenna that consists of a metallic patch and some parasitically-coupled elements mounted on a grounded dielectric-ferrite substrate. The metallic patch is fed by a proximity-coupled feed line placed between the ferrite and the dielectric layers. The parasitically-coupled elements are included to improve the impedance bandwidth of antenna and are excited through the metallic patch. The antenna utilizes the resonant modes of the structure which rotate only in the clockwise or counter clockwise direction. A semi-analytical solution based on the magnetic wall approximation shows that the resonance frequencies of the clock- and counter clockwise resonant modes differ significantly when operating in the frequency range where the effective permeability of the ferrite layer is negative. Moreover, there is good agreement between the model presented and full wave numerical simulations. For the proposed antenna, the results show that the radiation bandwidth is more than 15.5% and the 3 dB axial ratio (AR) bandwidth is more than 50%. The proposed antenna is easy to design and fabricate, does not require a complicated feeding network, and has a wideband and wide-angle circular polarization.
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In this article, a coplanar-waveguide (CPW)-fed dual-band antenna for applications of the multisystem integration has been demonstrated. The resonance analysis of the stepped-impedance (SI) monopole is presented by using the transmission-line analysis method. The frequency-response characteristics of the SI-monopole, such as the resonance condition and harmonic response, are systematically summarized. Furthermore, utilizing several simple techniques, such as bent feeding topology, asymmetric ground plane, and an L-shaped slot etched in the ground plane, a right-hand circularly polarized (RHCP) radiating wave at 1.57 GHz and a left-hand circularly polarized (LHCP) radiating wave at 2.33 GHz are excited for the applications of the global positioning system (GPS) and the satellite digital audio radio (SDAR) service system. After optimization of the geometrical parameters of the proposed antenna, the measured impedance bandwidths of a reflection coefficient less than −10 dB range from 1.40 to 2.98 GHz and from 4.48 to 6.27 GHz, and thus covers most of the commercial wireless communication systems, such as GPS, digital cellular system (DCS), personal communication system (PCS), international mobile telecommunications (IMT)−2000, wireless local area networks (WLAN), and long-term evolution (LTE) 2300/2600. The measured 3-dB axial ratio (AR) bandwidths are about 80 MHz at 1.57 GHz and 100 MHz at 2.33 GHz.
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A moon-shaped printed monopole antenna with modified ground plane is proposed for broadband circularly polarized (CP) radiation. Proposed monopole antenna consists of a moon-shaped radiator with a microstrip feed line. The moon-shaped radiator and its ground-plane shaped are optimized for broadband CP radiation. Impedance matching is improved using the quarter-wave transformer along with microstrip line. The measured results of the prototype antenna on FR4 substrate are 1.67 GHz (2.08−3.75 GHz) for 2.5-VSWR bandwidth, 1.48 GHz (2.28–3.76 GHz) for 3-dB axial ratio (AR) bandwidth, and gain around 1.6 dBic across the 3-dB AR bandwidth. Overall antenna volume is 0.466λ0 × 0.70λ0 × 0.008λ0 at 3.0 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1135–1139, 2015
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A novel loop-like monopole antenna with dual-band circular polarization (CP) for the reception of WiMAX and WLAN is designed and implemented in this paper. The antenna consists of a radiating patch which is composed of an annular-ring linked by a square ring over the corner and a ground plane with embedded rectangular slit. The broad impedance bandwidth is achieved based on a novel monopole structure which is the combination of two perturbed loops and the perturbation causes the generation of right-hand circular polarization (RHCP) at 3.52 GHz and left-hand circular polarization (LHCP) at 5.75 GHz. In addition, by embedding a rectangular slit on the ground, the impedance bandwidth can be greatly enhanced. The measured results show that the proposed monopole antenna has an impedance bandwidth of 3.65 GHz from 2.65 to 6.3 GHz, reaching the particularly broad bandwidth of 81.6%. Furthermore, the measured 3- dB axial ratio (AR) bandwidths are about 440MHz at the lower band (3.52 GHz) and 220MHz at the upper band (5.75 GHz). The radiation characteristics of the implemented antenna are also presented.
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Conference Paper
This paper presents a Z-shaped printed monopole antenna for wideband circularly polarized radiation. The antenna consists of a Z-shaped strip radiator fed by a microstrip line attached the Z-shaped strip. The antenna is fabricated on a thin FR4 dielectric substrate. The measured performances of the antenna are 1.28 GHz (2.53-3.81 GHz) for 10-dB return loss bandwidth, 1.75 GHz (2.25-4.0 GHz) for 3-dB axial ratio bandwidth, and gain around 1.7 dBic over the 3-dB axial ratio bandwidth. The volume of the proposed antenna is 50 mm × 40 mm × 0.8 mm.
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A circularly polarised printed dipole-like antenna employing asymmetrical arms and an orthogonal slit in the ground plane is presented. It is fed by a stepped microstrip line which connects to the shorter arm. By utilising surface currents on the asymmetrical arms and the orthogonal feedline structure, circular polarisation is realised. Experimental and numerical data are in agreement and the measured results show a fractional impedance bandwidth of 41.3% (1.77-2.69 GHz) and a wide axial-ratio bandwidth of 38.4% (1.81-2.67 GHz).
Article
A novel broadband monopole antenna design with wideband circular polarization (CP) characteristic is presented. This antenna consists of a feed line and a step-shaped ground plane which is formed by cutting a notch in the upper left corner of an asymmetric ground plane. The asymmetric ground plane is capable of exciting two orthogonal electric field vectors with equal amplitude and 90° phase difference (PD) for CP. By cutting a notch, the 10-dB impedance-bandwidth can be enhanced greatly and the 3-dB axial ratio (AR) bandwidth is also improved meanwhile. The measured impedance-bandwidth is about 5.96 GHz (84.7%) from 4.06 to 10.02 GHz, and the measured AR-bandwidth is about 2.64 GHz (36.5%) from 5.91 to 8.55 GHz. The results show that the antenna can achieve wide impedance-bandwidth and wide AR-bandwidth simultaneously.
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A wideband printed rectangular monopole antenna for circularly polarised wave is proposed. The radiation characteristics of the wideband circular polarisation are achieved by designing the antenna asymmetrically. With simulations, the relationships between the antenna??s geometrical parameters and the antenna's characteristics (axial ratio of circularly polarised wave and return loss) are clarified. The operational principle for wideband circular polarisation is explained by the simulated electric current distributions. Moreover, the simulated axial ratio, return loss, radiation patterns and gain are compared with the measured results. The simulated and measured bandwidths (3 dB axial ratio with a 10 dB return loss) are ∼56.2% (1.78–3.17 GHz) and 51.4% (1.82–3.08 GHz), respectively.
Conference Paper
A printed rectangular monopole antenna for circular polarization is proposed. By simulations, the relationships of antenna geometrical parameters and the axial ratio of circularly polarized wave are clarified. Moreover, the calculated return loss and axial ratio are compared with measured results. The calculated and measured bandwidths (the return loss ≤-10dB with axial ratio ≤3dB) are approximately 53% and 60%, respectively.
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A novel circular dual band, dual sense circularly polarised (CP) monopole antenna for GPS and WLAN applications is presented. A CP bandwidth larger than 40% can be attained simply by creating rectangular slots on the circular patch of the microstrip line. By adding rectangular slots, the 3%dB axial ratio bandwidth and the %10%dB impedance bandwidth can be greatly improved. Novel and simple design of the radiating patch, large 3%dB axial ratio bandwidth and compact size of the antenna are the novel aspects of this work.
Article
A wideband circularly polarised antenna is presented. It features an inverted L-shaped monopole, an inverted U-shaped strip and a slot-loaded ground plane. The ground plane and U-shaped strip share the same layer, and the L-shaped strip is printed in the opposite layer. The U-shaped strip is useful in increasing the return-loss bandwidth, and the slot on the ground is found crucial to widen the axial-ratio bandwidth. With a proper length of the slot, the experimental results show that the antenna has a return-loss bandwidth of 2.0 GHz (2.05-4.05 GHz) and an axial-ratio bandwidth of 1.8 GHz (2.0-3.8 GHz).
Article
A novel CPW-fed planar printed monopole antenna with broadband circular polarization (CP) characteristic is presented. The proposed antenna consists of a rectangle patch and an improved ground-plane. By appropriately adding a vertical stub and cutting a horizontal slit on the ground-plane, the impedance bandwidth of the antenna is enlarged, and its wide axial-ratio (AR) bandwidth is achieved. The measured results show that the proposed antenna has not only a broad 3-dB AR bandwidth of 44.9% (2.65 GHz, 4.58-7.23 GHz) with respect to the CP center frequency 5.90 GHz, but also a wide 10-dB return loss bandwidth of 76.9% (4.35 GHz, 3.48-7.83 GHz) centered at 5.66 GHz.
Article
This article proposes a new single microstirp-fed circularly polarized printed antenna for global positioning satellite (GPS) receivers. The antenna consists of two orthogonal monopoles, generating two orthogonal linearly polarized waves of equal amplitudes with a 90-degree phase shift in the operation band. In contrast to typical GPS patch antennas, the proposed antenna has much wider axial ratio bandwidth. In addition, the antenna can be simply designed, cost-effectively manufactured, and easily merged with the related circuit board. A prototype antenna was created and investigated, and the experimental results obtained also demonstrate its low sensitivity to manufacturing uncertainty.
Article
Novel broadband monopole antenna designs with dual-band circular polarization (CP) are presented. The proposed antenna comprised of a ground plane embedded with an inverted-L slit, which is capable of generating a resonant mode for broadband impedance-bandwidth, and excites two orthogonal E vectors with equal amplitude and 90deg phase difference (PD) for radiating left-hand circular polarization (LHCP) at 2.5 GHz and right-hand circular polarization (RHCP) at 3.4 GHz. A bevel is cut in the rectangular radiator to increase the impedance-bandwidth. The measured result of the impedance-bandwidth is about 4.46 GHz from 2.12 to 6.58 GHz; the 3-dB axial ratio (AR) bandwidths are about 150 MHz at the lower band (2.5 GHz) and 230 MHz at the upper band (3.4 GHz). Furthermore, embedding an I-shaped slit in the rectangular radiator and adding an I-shaped stub in the ground plane, the impedance-bandwidth can be further increased to 6.30 GHz (2.17-8.47 GHz), and the 3-dB AR-bandwidth at the upper band is greatly enhanced from 230 to 900 MHz.
Article
A microstrip-fed broadband circularly polarised (CP) monopole antenna was studied. A broad impedance bandwidth and wide axial ratio bandwidth (AR-BW) could be achieved simultaneously. This antenna used a conventional monopole architecture, except for its deforming ground plane and asymmetric-feed approach. The asymmetric-feed was used to provide an orthogonal component distinct from its original linear polarisation. In addition, by embedding a slit and a stub on the ground plane, this antenna could generate CP wave radiation and achieve a broad impedance bandwidth. According to the measurement results, the impedance bandwidth was 6.56 GHz for a 10 dB return loss, which covered a range of 2.32 8.88 GHz. The AR-BW was 1.2 GHz for a 3 dB AR, which covered a range of 3.2 4.4 GHz.