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Characteristic Mode Analysis Based Design of a Sub-THz Slotted Patch Antenna for High-Speed Wireless Communication Networks
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A triple band rectangular slotted antenna for THz applications has been reported in this study. Over a 10 dB impedance scale, the suggested antenna covers the frequency spectrums with a centre frequency of 0.73, 0.76, and 0.79 GHz. With a 0.75 GHz fundamental frequency, a rectangular patch antenna is first developed. Later, it is transformed into a rectangular ring, which provides triple band resonance across a 10 dB impedance bandwidth. The intended triple-band THz array that was built has a gain of up to 10 dBi and a directivity of 12 dB. Additionally, the array has a radiation efficiency of up to 85% throughout all spectral bands. After seeing and assessing the impact that the variation in the number of radiating pieces had on both the gain and the return loss, we came to this conclusion. Given this information, the developed antenna has been a potential choice for usage in satellite and space research as well as terrestrial applications.
Advances in recent communication systems require minimal weight, low cost, high performance and low-profile antenna to meet the demand for next generation wireless communication devices. Due to the saturation velocity, high electrical conductivity and high mobility, graphene patch antennas are preferably used in the Terahertz band region (THz). On the other hand, MIMO antenna is usually required to compensate for the high path losses and atmospheric attenuation in THz frequency band spectrum and to offer higher data rates. In this work, a fractal MIMO antenna structure is placed on SiO2 substrate embedded with Photonic Band Gap crystal (PBG). The designed MIMO antenna structure obtains an impedance bandwidth of 1590 GHz covering an effective frequency spectrum from 1.41 to 3.0 THz with a fractional bandwidth of 72.10%. Furthermore, the proposed antenna offers peak radiation efficiency of 74.5% and gain of 4.60 dBi at the resonant frequency of 1.89 THz. The proposed MIMO antenna achieves isolation levels of greater than 25 dB throughout the entire working band and also maintains a compact dimensions of only 38 μm 25 μm. The suggested photonic crystal-based MIMO antenna offers superior MIMO metrics like ECC ≈ (0.00000000156), DG (≈10 dB), MEG (≈ 3 dB), TARC (≈ 42 dB) and CCL (≈0.00000000465 b/Hz/sec) at the resonant frequency of 1.89 THz. Hence, the prescribed MIMO radiator can be utilized for various applications such as threat detection, material characterization, near field communication, detection of explosive and medical imaging in the terahertz band.
A novel circularly polarised (CP) antenna design, termed differential mode (DM) and common mode (CM) design, is presented with equal‐amplitude in‐phase feed (EAIPF) in this article. At first, the CM and DM of the antenna are excited separately using the dual ports. Then, the CP antenna is obtained with EAIPF by adjusting the radiation amplitude of CM and DM, due to the orthogonality with a 90° phase difference for CM and DM. Finally, the obtained operational bandwidth of the presented antenna is 1.75–2.30 GHz (27.1%), with a reflection coefficient < −10 dB and axial ratio <3 dB. This CP antenna design eliminates the need to design 90° phase shifter as well as reduces the complexity of the feed structure of CP antennas, providing a novel idea for the design of CP antennas.
In this paper, a circular patch antenna with cross-shaped slot is designed. Graphene has been used in the design of the said antenna. The proposed antenna structure has frequency reconfigurable capability. The central frequency of the antenna is considered to be 1.6 THz as required by the design. The cross-shaped slot reconfigurable graphene-based microstrip patch antenna is realized on a SiO2 substrate. In the center of the designed circular patch antenna, a slot is placed in the form of two orthogonal physical arms, or in other words, a cross shape. And as a result, the distribution of the final current of the antenna will have an orthogonal domain in the farfield. Which will have a phase difference of 90 degrees. And this is the realization of circular polarization. In the range of 0.5 THz to 2 THz, cross-shaped slot reconfigurable graphene-based microstrip patch antenna has favorable conditions in terms of matching and polarization. Also, S11 is less than − 15 dB for the target range. The axial ratio is obtained less than 2 dB. Obtaining an axial ratio below 3 dB is ideal for providing circular polarization. Radiation efficiency is about 59%. Finally, the results of radiation efficiency, 2D and 3D radiation patterns, E-field distribution, H-field distribution and surface current distribution have been considered.
This work presents a 12-element 360° azimuth plane scanning planar circular antenna array for compact THz wireless devices. Proposed array comprises of 12 bow-tie Yagi-Uda directional antennas, operating within 0.235–0.322 THz band where each antenna achieves a maximum radiation beam for an angle of around 30°, arranged in a circular fashion to cover 360°. Individual antennas are stamped on a silicon dioxide (SiO2) dielectric substrate having compact dimensions of 1.35 mm × 1 mm × 0.06 mm and employ gold material of thickness 5 µm as a conducting material in the top and bottom planes. Maximum peak gain of each antenna is found to be 10.4 dBi at 0.322 THz within the operating band. Three parasitic elements are employed as directors to enhance the directional properties. Initially, a single element bow-tie Yagi-Uda antenna design is presented and then followed by a 6-element and 12-element circular antenna array design. Exhibiting compact dimensions, higher directivity, better performance and simple design lead to a suitable module for smart THz wireless scanning devices in the range of IEEE 802.15.3d (0.252–0.325 THz) standard and H-band (0.22–0.32 THz).
The paper presents the design and analysis of a sectored—circular microstrip terahertz antenna with the defective ground structure for Wireless Body Area Network (WBAN) and Multiple Input Multiple Output (MIMO) applications. The designed antenna is fed by a microstrip line feed and provides an impedance bandwidth of 11.844 THz (0.12–11.964 THz). To obtain the optimum performance the parametric analysis of patch and ground plane is carried out. A maximum gain of 17.32 dBi has been acquired by an antenna at 8.352 THz. Spatial diversity MIMO configuration of the proposed antenna is also discussed. The mutual coupling (S21) for the MIMO antenna is less than − 25 dB over the whole operational bandwidth, and all MIMO parameters are well within acceptable limits. The projected antenna's small size, wide bandwidth, and high gain make it appropriate for a wide range of wireless applications.
In this paper, a high-gain THz antenna array is presented. The array uses a polyimide substrate with a thickness of 10 μm, a relative permittivity of 3.5, and an overall volume of 2920 μm × 1055 μm × 10 μm, which can be employed for THz band space communication and other interesting applications. The dual-band single-element antenna is designed in four steps, while operating at 0.714 and 0.7412 THz with −10 dB bandwidths of 4.71 and 3.13 GHz, providing gain of 5.14 and 5 dB, respectively. In order to achieve a high gain, multiple order antenna arrays are designed such as the 2 × 1 antenna array and the 4 × 1 antenna array, named type B and C, respectively. The gain and directivity of the proposed type C THz antenna array are 12.5 and 11.23 dB, and 12.532 and 11.625 dBi at 0.714 and 0.7412 THz, with 99.76 and 96.6% radiation efficiency, respectively. For justification purposes, the simulations of the type B antenna are carried out in two simulators such as the CST microwave studio (CSTMWS) and the advance design system (ADS), and the performance of the type B antenna is compared with an equivalent circuit model on the bases of return loss, resulting in strong agreement. Furthermore, the parametric analysis for the type C antenna is done on the basis of separation among the radiating elements in the range 513 to 553 μm. A 64 × 1 antenna array is used to achieve possible gains of 23.8 and 24.1 dB, and directivity of 24.2 and 24.5 dBi with good efficiencies of about 91.66 and 90.35% at 0.7085 and 0.75225 THz, respectively, while the 128 × 1 antenna array provides a gain of 26.8 and 27.2 dB, and directivity of 27.2 and 27.7 dBi with good efficiency of 91.66 and 90.35% at 0.7085 and 0.75225 THz, respectively. All the results achieved in this manuscript ensure the proposed design is a feasible candidate for high-speed and free space wireless communication systems.
The Terahertz (THz) band (0.3-3.0 THz), spans a
great portion of the Radio Frequency (RF) spectrum that is
mostly unoccupied and unregulated. It is a potential candidate
for application in Sixth-Generation (6G) wireless networks, as
it has the capabilities of satisfying the high data rate and
capacity requirements of future wireless communication systems.
Profound knowledge of the propagation channel is crucial in
communication systems design, which nonetheless is still at its
infancy, as channel modeling at THz frequencies has been mostly
limited to characterizing fixed Point-to-Point (PtP) scenarios
up to 300 GHz. Provided the technology matures enough and
models adapt to the distinctive characteristics of the THz wave,
future wireless communication systems will enable a plethora
of new use cases and applications to be realized, in addition
to delivering higher spectral efficiencies that would ultimately
enhance the Quality-of-Service (QoS) to the end user. In this
paper, we provide an insight into THz channel propagation char-
acteristics, measurement capabilities, and modeling techniques
for 6G communication applications, along with guidelines and
recommendations that will aid future characterization efforts
in the THz band. We survey the most recent and important
measurement campaigns and modeling efforts found in literature,
based on the use cases and system requirements identified.
Finally, we discuss the challenges and limitations of measurement
and modeling at such high frequencies and contemplate the future
research outlook toward realizing the 6G vision.
Wireless communication at the terahertz (THz) frequency bands (0.1-10THz) is viewed as one of the cornerstones of tomorrow’s 6G wireless systems. Owing to the large amount of available bandwidth, if properly deployed, THz frequencies can potentially provide significant wireless capacity performance gains and enable high-resolution environment sensing. However, operating a wireless system at high-frequency bands such as THz is limited by a highly uncertain and dynamic channel. Effectively, these channel limitations lead to unreliable intermittent links as a result of an inherently short communication range, and a high susceptibility to blockage and molecular absorption. Consequently, such impediments could disrupt the THz band’s promise of high-rate communications and high-resolution sensing capabilities. In this context, this paper panoramically examines the steps needed to efficiently and reliably deploy and operate next-generation THz wireless systems that will synergistically support a fellowship of communication and sensing services. For this purpose, we first set the stage by describing the fundamentals of the THz frequency band. Based on these fundamentals, we characterize and comprehensively investigate seven unique defining features of THz wireless systems: 1) Quasi-opticality of the band, 2) THz-tailored wireless architectures, 3) Synergy with lower frequency bands, 4) Joint sensing and communication systems, 5) PHY-layer procedures, 6) Spectrum access techniques, and 7) Real-time network optimization. These seven defining features allow us to shed light on how to re-engineer wireless systems as we know them today so as to make them ready to support THz bands and their unique environments. On the one hand, THz systems benefit from their quasi-opticality and can turn every communication challenge into a sensing opportunity, thus contributing to a new generation of versatile wireless systems that can perform multiple functions beyond basic communications. On the other hand, THz systems can capitalize on the role of intelligent surfaces, lower frequency bands, and machine learning (ML) tools to guarantee a robust system performance. We conclude our exposition by presenting the key THz 6G use cases along with their associated major challenges and open problems. Ultimately, the goal of this article is to chart a forward-looking roadmap that exposes the necessary solutions and milestones for enabling THz frequencies to realize their potential as a game changer for next-generation wireless systems.
Graphene-based patch antennas are rapidly gaining interests in communication technologies for high-speed data transmission due to the exciting properties of graphene material. Herein, we designed a high-performance circular patch antenna for terahertz band application with graphene as the radiating patch. For the protection of patch against environmental jeopardies and enhancement of antenna performance, a thin layer of Teflon (εr = 2.1) as superstrate is used, and overall antenna performance is evaluated. The designed antenna operates around 7 THz with amazing S11 of − 75.66 dB and VSWR of 1.0003. The designed antenna is highly efficient with radiation efficiency of 97.21% and a very high gain of 7.286 dB. The designed antenna is also analysed for different dielectric materials used as the covering superstrate layer. Where the introduction of higher dielectric constant materials as superstrate layer increases the antenna gain significantly, it also reduces the bandwidth and efficiency of the designed antenna at terahertz band. An antenna gain of 7.392 dB is achieved for glass (εr = 4.82) as superstrate material.
An Indium-doped Tin Oxide (ITO) based optically transparent nano-antenna is presented in this paper. E-shaped patch is used to resonate at 0.76 THz. Despite of high fractional bandwidth, the radiation efficiency as well as gain of the ITO based antennas are low due to high resistivity and low conductivity of ITO thin films. To overcome this limitation,
carbon nano tube (CNT) is used as cover over radiating patch of the proposed antenna. As a result, due to high conductivity of CNT, along with gain and efficiency, the fractional
bandwidth of the proposed antenna is also increased. Characteristic mode analysis (CMA) is carried out to provide more insightful physical characteristics of the proposed
antenna. It helps to understand the structural optimization and to determine the operating frequency. Moreover, a copper based non-transparent E-shaped patch antenna, resonated at 0.76 THz is also designed to compare with the proposed antenna. The proposed antenna has fractional bandwidth of 21% which is much better than conventional patch antenna and some previous transparent antennas. A peak gain of 4.9 dBi is obtained at 0.76 THz with good radiation performance. The designed antenna is suitable for satellite communication because of its broad bandwidth, reasonable radiation efficiency, sufficient gain, light weight and compactness.
As fifth generation (5G) research is maturing towards a global standard, the research community has started to focus on the development of beyond-5G solutions and the 2030 era, i.e. 6G. In the future, our society will be increasingly digitised, hyper-connected and globally data driven. Many widely anticipated future services will be critically dependent on instant, virtually unlimited wireless connectivity. Mobile communication technologies are expected to progress far beyond anything seen so far in wireless-enabled applications, making everyday lives smoother and safer while dramatically improving the efficiency of businesses. 6G is not only about moving data around — it will become a framework of services, including communication services where all user-specific computation and intelligence may move to the edge cloud. The white paper presents key drivers, research requirements, challenges and essential research questions related to 6G. The focus is on societal and business drivers; use cases and new device forms; spectrum and key performance indicator targets; radio hardware progress and challenges; physical layer; networking; and new service enablers. Societal megatrends, United Nations’ sustainability goals, lowering carbon dioxide emissions, emerging new technical enablers as well as ever increasing productivity demands are introduced as critical drivers towards 2030 solutions. This white paper is the first in a series of 6G Research Visions based on the views that 70 invited experts shared during a special workshop at the first 6G Wireless Summit in Finnish Lapland in March 2019.
Abstract:
In this paper, a wide bandwidth (26.4 GHz) and very small sized (180×210×10 μm3) slotted patch terahertz (THz) rectangular microstrip antenna using photonic band gap (PBG) substrate and defected ground structure (DGS) has been proposed and analyzed. At first a very compact with dimension of μm range rectangular microstrip patch antenna (RMPA) was designed by using computer simulation technology microwave studio (CST-MWS) at the operating frequency of 0.685 THz, which shows return loss of -30.552 dB, wide bandwidth of about 26 GHz, gain of 5.145 dBi, directivity of 6.727 dBi and VSWR of 1.061. Then we introduced PBG structure as substrate by creating same distant as well as same sized air gaps on the substrate. In that case the performance of the antenna is improved significantly than the previous one. Its return loss decreased to -38.973 dB at resonating frequency 0.701 THz. Its gain and directivity get increased to 5.156 dBi and 6.833 dBi respectively. Bandwidth is also enhanced compared to the previous one with a VSWR of 1.023. Next we have done some experiment by creating defects in ground plane. We optimized the dimensions of the defects and got better performance of the antenna having 0.704 THz resonant frequency with more minimized return loss of -47.862. Gain of this antenna is 5.090 dBi and directivity is increased to 6.835 dBi. Its VSWR is of 1.008 with the improved bandwidth. Finally, we have made some circular slots on the radiating patch and got best results. The final design of antenna resonates at center frequency of 0.703 THz with a return loss of -50.948 dB. The gain and directivity of the proposed antenna are of 5.075 dBi and 6.833 dBi respectively. The antenna shows VSWR of 1.006 which is very much close to unity (1) with the enhanced bandwidth compared to the all previously designed antenna.
A through wafer vertical micro-coaxial transition flushed in a silicon substrate has been designed, fabricated, and tested. The transition has been designed using radio frequency (RF) coaxial theory and consists of a 100 μm inner diameter and a 300 μm outer diameter, which corresponded to a 1 : 3 inner/outer diameter ratio. The transition's through silicon structure has been achieved using standard photolithography techniques and Bosch's process for deep reactive ion etching (DRIE). The coaxial vias of the transition have been successfully metalized with a diluted silver paste using a novel filling method. To measure the behavior of the transition at high frequencies, coplanar waveguide (CPW) lines matched at 50 ohms have been integrated on the front and backside of the device. Measurement results show that the transition demonstrate good results with a reflection coefficient better than -10 dB at high frequencies from 15 GHz-to-60 GHz. Results also indicate that the transition has good signal transmission with less than -1:8 dB insertion loss up to 65 GHz. By eliminating the need for rigorous bonding techniques, the transition is a low-cost and durable design that can produce high input/output ratios ideal for commercial products.
The simplicity and intuitive design of traditional circularly polarized (CP) patch antennas, such as the truncated corner patch antenna, has led to their widespread popularity. However, they are limited to a narrowband performance on the order of 0.1%–2% for simultaneously good S11 and axial ratio (AR). We will prove theoretically that this is a direct result of the probe reactance hindering the use of thicker substrates to increase the bandwidth. Furthermore, we propose a novel compensation technique to enhance the bandwidth capabilities of these CP patch antennas. Our method inserts a capacitive element, such as an annular gap or parallel plate, in series with the probe inductance to remove its effect. We demonstrate this technique with simulations and measurements to obtain AR-S11 bandwidth capabilities as high as 12.6%. To the authors' best knowledge, this is the first time that capacitive compensation and thick substrates have been jointly employed to enable broadband CP patch antennas.
In this paper, a novel dual-band photonic band gap (PBG) structure was proposed and applied to a dual-band microstrip antenna. The antenna resonates at 1.267 THz and 1.502 THz, exhibiting reflection coefficients of −58.177 dB and −49.462 dB, and gains of 3.173 dBi and 5.232 dBi, respectively. Compared with the microstrip antenna based on the homogeneous silicon substrate, the designed dual-band antenna based on the novel PBG structure shows improved impedance matching, radiation efficiency, and gain. The paper simulated and analyzed the impacts of different filling dielectric materials and the variations of dimensions, position, period, and corrugation depths of the dual-band PBG structure on the resonances of the antenna. It is expected that the proposed novel dual-band PBG structure has great application potentials, and such cancer diagnosis is done by utilizing the radiation characteristics of the antenna.
This paper presents an opportunity to integrate an innovative photonic band gap (PBG) structure (based on the metamaterials concept) into design topology and manufacture Quasi-Yagi antennas. The design aims to implement PBG structure directly into the antenna design. That allows a galvanic connection between the antenna and the metamaterial to improve Quasi-Yagi characteristics. Various simulations and measurements have been made showing the synthesized antenna system functionality and its applicability for different practical applications in communication systems - due to the operating frequency 2.4GHz.
The appropriate choice of patch and substrate materials has great significance in the performance of the terahertz (THz) microstrip patch antenna. The resonant frequency is dependent on various factors such as dimensions of the patch, substrate thickness, and permittivity. In this work, initially, a microstrip antenna with a silicon substrate was analyzed for different patch materials such as copper, graphene, and gold with a central operating frequency of 300 GHz. The result reveals that the graphene patch has a maximum bandwidth of 1.49 GHz and ideal radiation efficiency. Then, adopting graphene as a patch material, the performance of the antenna is analyzed on the basis of return loss, voltage standing wave ratio (VSWR), radiation efficiency, bandwidth, and gain with different substrate materials such as quartz, silicon, silicon dioxide, and silicon nitrate. The results show that quartz has an optimal performance by generating higher bandwidth and radiation efficiency when compared to other chosen substrate materials.
In this paper a novel high efficiency microstrip patch antenna is presented for terahertz applications. The proposed antenna is low-cost because its substrate is FR-4 and has a high radiation efficiency (more than 77.5%). By applying fractal structure the radiating length of the current path is increased and the size of the antenna is decreased. The antenna has acceptable properties in terahertz frequency band; such as: return loss, bandwidth of 118% (0.434–1.684 THz), efficiency, gain (Max. gain of 5.72 dBi), size (150 × 150 × 9.6 μm) and very low cost. These features are improved by optimization especially by cutting a rectangular notch and adding a strip to the top right section of the antenna. The antenna has numerous application introduced in content. In order to investigate the influences of the notch, the added strip, number of meshes, running time and maximum used RAM computational comparison between frequency and time domains is presented for four different antenna geometries.
The cryogenic process is used to drill 400μm thick silicon wafers. It is first studied on single side masked substrates. Holes of 14μm in diameter are 210μm deep after 30min, representing an average etch rate as high as 7μmmin−1. This process enables the drilling of holes of 12μm in diameter within 1h 06min. We investigate the effect of the substrate temperature and show that the process is very sensitive to this parameter. It is the main issue in cryo-etching. We use a recent cryogenic chuck with a good temperature uniformity. This last point was characterized using a new method we developed. It is based on the dependencies of columnar microstructures dimensions on the temperature. We have shown that the maximum temperature variation is less than 2°C on the cryogenic chuck.
It is shown that the efficiency of a small antenna can be substantially increased by properly locating it on its support structure. Characteristic modes are used to determine the optimum location and frequency.
A theory of characteristic modes for conducting bodies is developed starting from the operator formulation for the current. The mode currents form a weighted orthogonal set over the conductor surface, and the mode fields form an orthogonal set over the sphere at infinity. It is shown that the modes are the same ones introduced by Garbacz to diagonalize the scattering matrix of the body. Formulas for the use of these modes in antenna and scatterer problems are given. For electrically small and intermediate size bodies, only a few modes are needed to characterize the electromagnetic behavior of the body.
Design and analysis of novel microstrip patch antenna on photonic crystal in thz
- R K Kushwaha
- P Karuppanan
- L Malviya
Dassault Systems, France
- Cst-Mws
Mobile data traffic outlook
- T Ericsson
T. Ericsson, "Mobile data traffic outlook," Ericsson Mobility Report data
and forecasts, 2021.
Computer Simulation Technology
- Cst-Mws
CST-MWS, A electromagnetic tool, i.e. Computer Simulation
Technology,, Dassault Systems, France,, 2021, Available: https:
//www.3ds.com/products-services/simulia/products/cst-studio-suite/.