Adaildo G. D’Assunção’s research while affiliated with Federal University of Rio Grande do Norte and other places

... Studies have explored innovative designs like dual-band miniaturized FSSs with high selectivity, providing efficient filtering of electromagnetic waves in multiple frequency bands [11]. Additionally, miniaturized multiband FSSs with wide frequency ratios have been developed, demonstrating the ability to operate across various frequency ranges while maintaining compact dimensions [12]. These innovations highlight the continuous evolution of FSS technology to meet the demands of modern wireless communication systems and electromagnetic interference mitigation strategies [13]. ...

Reference:

Frequency Selective Surfaces: Design, Analysis, and Applications

... A 2.5D FSS with concentric rings and 44 via holes is presented in [8] to achieve significant size reduction in a dual-band FSS operating at 2.4-and 5-GHz Industrial Scientific and Medical (ISM) bands. Quadrapule L slots are used in the FSS of [9] to obtain dual-band resonance at 900 MHz and 2.4 GHz suitable for mobile communication systems. Some of the other important findings on wideband bandpass FSS have been reported in [10][11][12]. ...

Reference:

An Ultra‐Thin Dual‐Polarized Bandpass Frequency Selective Surface for 2.45‐/5.8‐GHz ISM Bands

... In recent years, the rapid development of accessible wireless communication demanded consistently high data rates and quality of service. 1 Wireless cellular (4G) systems are upgraded to support high data transfer rates. 2 The 5th generation (5G) networks have been developed to address these issues and offer several benefits, including extremely high data rates, less latency, low multipath fading, outstanding reliability, and more channel capacity. 3 There needs to be more than one antenna to provide the abovementioned number of benefits in 5G. Hence, multipleinput multiple-output (MIMO) antenna technology has a lot of attention with the advancement of wireless 5G technology because of its outstanding capacity to increase data rates and channel capacity. 4 The design challenges of the MIMO antenna require compact size; the mutual coupling has to be less than −15 dB and satisfies performance metrics. ...

Reference:

Isolation enhancement of distinct element dual polarized compact MIMO antenna for 5G/WLAN application

... It was shown that the dielectric permittivity and the loss tangent can be separately determined by means of the variations of the resonant frequency and the unloaded quality factor, respectively 3 . Nogueira et al. proposed a complementary split-ring resonator (CSRR) sensor for the characterization of dielectric slabs with a similar parameter extraction strategy 42 . Alimenti et al. particularized this dielectric permittivity and loss tangent extraction technique to 3-D-printing materials with a split-ring resonator (SRR) sensor 37 . ...

Reference:

Multi-parameter simultaneous extraction with a novel microwave sensor based on coupled resonators

... Several types of dual-mode resonators in the form of coupled-line structures with stubs [5][6][7][8][9], loop [10][11][12], ring [13,14], and patch [15][16][17][18][19][20][21][22][23] have been explored in the literature and also widely applied in BPF designs. Though reasonable filter performance can be realized in [5,6] and [8,9], the resultant structure is fairly large. ...

Reference:

Novel fractal-based dual-mode quasi-elliptic microstrip band-pass filter for WLAN applications

... Figure 2c depicts the parameters used in Orange for the NN model. • A Decision Tree is a flowchart-like structure of decisions and their possible outcomes, starting with a root node that branches into new nodes until reaching a leaf node, which represents a result [30]. Figure 2d illustrates the parameters used in Orange for the DT model. ...

Reference:

Forecasting Raw Material Yield in the Tanning Industry: A Machine Learning Approach

... A set of unsymmetrical dual-feed antennas with two isolated ports and a single shared radiator are reported in [9]. MIMO antenna layout uses a T-shaped monopole as the first element and a square patch as the second element to effectively reduce the mutual coupling [10]. Moreover, to increase the system variety and assure the operation across desired lower UWB range, the MIMO system utilizes two distinct antenna elements. ...

Reference:

Circumferential slots based decoupled wideband MIMO antenna for 5G and sub-6 GHz applications

... The emergence of metamaterials with different resonator unit shapes has played a great role in reducing the complexity incurred due to the addition of extra structures, thus improving the performance of the antenna [26,27]. Metasurface structures are typically two-dimensional arrays of small scatters or apertures that are geometrically arranged in order to achieve some desirable electromagnetic behavior [28][29][30][31]. Metasurface structures such as frequency selective surfaces (FSSs) have been widely used to improve the low gain and narrow bandwidth performance of planar antennas owing to their low cost and small profile, in addition to their immense transmission and reflection potentials [32][33][34]. ...

Reference:

Monopole Antenna with Enhanced Bandwidth and Stable Radiation Patterns Using Metasurface and Cross-Ground Structure

... Its radiation efficiency is estimated to be above 99.91%, while a large gain and bandwidth of 4.24 and 2.89 GHz are observed for it, respectively, making it particularly valuable for military, medical as well as telecommunication applications [39][40][41][42][43]. Table 6 enlists and compares the performance parameters of the investigated antenna with earlier reported work [43][44][45][46][47][48]. BSFO owes a considerably broad bandwidth of 2.89 GHz implying a large range of microwave frequency signals can be transmitted and good capability of electrical to wireless transmission in terms of radiation efficiency of 99.91%. ...

Reference:

Structural, electrical, and impedance properties of Co and Sn doped Ba0.5Sr0.5Fe12-2xO19 hexaferrite ceramics (0 ≤ x ≤ 1) and their evaluation for antenna application

... Among others, the class of printed antennas are of special interest, since they exhibit several advantages such as low weight, ease of fabrication, low cost for mass production and flexibility in terms of polarization and input impedance [1]. Printed wideband end-fire topologies are available as well, such as the printed Yagi-Uda [2], the quasi-Yagi-Uda [3] and the printed log-periodic antenna [4], [5]. ...

Reference:

A Detailed Design Procedure for Printed Log-Periodic Antennas with Koch Fractal Dipoles