PIER C | PIER Journals

2023-05-28

PIER C

Vol. 133, 109-120, 2023

doi:10.2528/PIERC23020901

download: 4

A Novel Quadrangular Slotted DGS with a Wideband Monopole Radiator for Fifth-Generation Sub-6 GHz Mid-Band Applications

Idrish Shaik Sahukara Krishna Veni

The demand for high data rate, good channel capacity, and reliability is always the primary area of concern in the modern era of wireless communication systems. The 5G standards have the fortitude to bring about rapid data transfer speeds, instantaneous connectivity, large data capacities, and minimal latency. In this paper, a novel quadrangular slotted defected ground structure (QSDGS) that incorporates a microstrip wide band antenna (WMA) was proposed for 5G n46/n47/n79 and n102 band applications. The DGS was represented on the ground plane by four rectangular looped slots. An inset feeding technique was employed on this slotted patch antenna. This DGS loaded patch antenna structure was mounted on an RT Duriod 5880 (ε_r = 2.2, loss tangent = 0.0009) with dimensions of 33 x 29 x 1.5 mm³ (0.44λ x 0.38λ x 0.02λ, where `λ' is calculated at lowest operating wavelength). This embedded antenna radiating structure resonated in a wide band ranging from 4.03 GHz to 6.32 GHz giving an impedance bandwidth of 2.3 GHz (50%), with a centre frequency of 4.44 GHz. The maximum gain was 4.7 dBi, and greater than 75% efficiency was obtained over the wide band. From the results extracted from the proposed antenna, it was found that the antenna was capable of covering the 5G NR n46/n47/n79 and n102 bands with significant bandwidth, gain, and efficiency. Thus, the antenna can be considered a potential contender for 5G mid-band wireless communication systems.

A Novel Quadrangular Slotted DGS with a Wideband Monopole Radiator for Fifth-generation Sub-6 GHz Mid-band Applications

2023-05-27

PIER C

Vol. 133, 97-107, 2023

doi:10.2528/PIERC23031501

download: 4

Adaptive Anisotropy Optimization Method for the Radial Point Interpolation Method in Lossy Media

Hichem Naamen Ajmi Ben Hadj Hamouda Taoufik Aguili

In this paper, we present a new numerical anisotropy optimization method for the three-dimensional (3D) radial point interpolation method (RPIM) in lossy media. Instead of evaluating the parameters of the artificial anisotropy or the scaling factors along the selected axes, as it is usually done in classical optimization algorithms, once the analytical expressions of these parameters have been determined, they are assigned at each node through their shape functions. By adaptive factor, we mean that its value varies in such a way to cancel the discrepancy between numerical and exact wavenumbers at each node. Doing such optimization at each node is indeed being possible during the calculation of these parameters by the RPIM dispersion relation. Therefore the numerical anisotropy is no longer optimized by averaging over the entire Cartesian grid but in each node direction. The RPIM numerical anisotropy adaptive optimization method (AOM) in lossy media is presented, and the theoretical adaptive factors are given as functions of nodes positions. Our results show that the numerical errors of the dispersion and the anisotropy are considerably reduced, after being optimized with the AOM. The proposed AOM scheme is applied for a 3D rectangular cavity in order to test its validity and evaluate the accuracy of the numerical results of our approach.

Adaptive Anisotropy Optimization Method for the Radial Point Interpolation Method in Lossy Media

2023-05-27

PIER C

Vol. 133, 81-95, 2023

doi:10.2528/PIERC23033106

download: 2

Improving Mutual Coupling in MIMO Antennas Using Different Techniques

Mostafa A. Nassar Heba Y. Soliman Rania M. Abdallah Esmat A. F. Abdallah

Two different MIMO antennas configurations are proposed in this paper for operation around 30 GHz with a bandwidth of 0.8 GHz. The proposed configurations are applicable in 5G, 6G and radar systems in Ka-band systems. Each of the proposed configurations consists of four identical rectangular elements where each element is connected to an impedance transformer for impedance mismatch improvement. Due to the close existence of antenna elements, mutual coupling can seriously degrade the gain, signal to noise ratio, matching characteristics, and efficiency of the MIMO antenna systems. To overcome performance degradation, several techniques such as Curved Edges (CE), Defected Ground Structure (DGS), and Band Gap Structure (BGS) are implemented. Simulation was carried out using the commercial Computer Simulation Technology (CST) and High Frequency Structure Simulation Software (HFSS). Prototypes are fabricated and measured. The experimental results show good agreement with the simulated ones. Improvement in the mutual coupling value from -21.4 dB to -27.2 dB also proves the practicality of this design.

Improving Mutual Coupling in MIMO Antennas Using Different Techniques

2023-05-24

PIER C

Vol. 133, 65-79, 2023

doi:10.2528/PIERC23040702

download: 41

Deep Learning Assisted Distorted Born Iterative Method for Solving Electromagnetic Inverse Scattering Problems

Harisha Shimoga Beerappa Mallikarjun Erramshetty Amit Magdum

This paper presents the deep learning assisted distorted Born iterative method (DBIM) for permittivity reconstruction of dielectric objects. The inefficiency of DBIM to reconstruct strong scatterers can be overcome if it is supported with Convolutional Neural Network (CNN). A novel approach, cascaded CNN is used to obtain a fine resolution estimate of the permittivity distribution. The CNN is trained using images consisting of MNIST digits, letters, and circular objects. The proposed model is tested on synthetic data with a different signal-to-noise ratio (SNR) and various contrast profiles. Thereafter, it is verified by means of experimental data provided by the Institute of Fresnel, France. Reconstruction results show that the proposed inversion method outperforms the conventional DBIM method in terms of accuracy as well as convergence rate.

Deep Learning Assisted Distorted Born Iterative Method for Solving Electromagnetic Inverse Scattering Problems

2023-05-23

PIER C

Vol. 133, 51-63, 2023

doi:10.2528/PIERC23020703

download: 10

A Novel Wideband Beamforming Antenna for 5G Applications by Eliminating the Phase Shifters and Crossovers from the Butler Matrix

Aicha Bembarka Larbi Setti Abdelwahed Tribak Hafid Tizyi Mohssine El Ouahabi

In this study, a novel Switched Beam Antenna (SBA) system is proposed and experimentally validated for C-Band applications. The system is made up of a 4 × 4 Butler matrix, whose outputs are connected to four square-looped radiator antenna elements. The originality of the proposed work depends on the construction of a miniaturized beamforming network with minimal complexity, low loss, and low expense. Moreover, designing a system with a broad frequency range enables its use in a variety of applications. Miniaturization is achieved by eliminating the crossover and integrating the 45˚ shifter into the 90˚ hybrid coupler, as well as tilting the antenna array (i.e., making the Butler matrix output and the feed line of the antenna element orthogonal). The simulated results of the phase difference between the suggested Butler matrix outputs closely match the -45˚-135˚ theoretical calculations. The SBA measured results show a wide bandwidth and low insertion loss of 63.64% (4.21-8.14 GHz) and -4.89 dB, respectively. Four orthogonal beams are produced by the proposed structure's input ports 1-4 when they are excited. These beams are aligned at angles of -10˚, 60˚, -60˚, and 10˚ at 5.7 GHz.

A Novel Wideband Beamforming Antenna for 5G Applications by Eliminating the Phase Shifters and Crossovers from the Butler Matrix

2023-05-22

PIER C

Vol. 133, 39-49, 2023

doi:10.2528/PIERC23032502

download: 11

Study on Electromagnetic Exposure of High-Speed Rail-Way Platform Staff Workers Induced by Contact Wires

Changqiong Yang Mai Lu

The bodies of platform staff workers in high-speed railway stations absorb induction electric field when exposed to the electric field environment of contact wires with 25 kV high-voltages. To analyze the safety of electromagnetic exposure of the station platform staff workers with different numbers of tracks, this paper establishes a model with 6 tracks, 2 platforms, and 4 staff workers on the platform simulating the actual situation. It then analyzes the distribution of induction electric field present in their human body tissues, which in the electric field environment is generated by the high voltages of the contact wires of 1 track, 3 tracks, 6 tracks, respectively. Calculation results show that the maximum induction electric field of staff worker on the platform with different track numbers appears at the scalp, and the electric field intensity levels in the skull and brain are relatively small. For example, on the two platforms with 6 tracks, the maximum induction electric field of the staff worker is found in the scalp, and the values are 58.86 times and 1688.52 times of those of the skull and brain, respectively. For the staff worker at the safety white line, the maximum induction electric field in a human central nervous system is 0.61 mV/m, which is far less than the basic limit of 100 mV/m occupational exposure in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. With the increase in the number of tracks, the maximum induction electric field of the staff also increases correspondingly at the same position. Research results can provide data reference for the formulation of electromagnetic protection and standards for high-speed railway platform staff workers.

Study on Electromagnetic Exposure of High-speed Rail-way Platform Staff Workers Induced by Contact Wires

2023-05-17

PIER C

Vol. 133, 27-38, 2023

doi:10.2528/PIERC23021601

download: 35

A Low-Profile Electrically Small Antenna with a Circular Slot for Global Positioning System Applications

Katireddy Harshitha Reddy Madhavareddy Venkata Narayana Govardhani Immadi P. Satyanarayana Kolasani Rajkamal Ambati Navya

A flexible, planar electrically small antenna (ESA) with omni directional radiation pattern is designed and fabricated for GPS and WLAN applications resonating at 1.5 GHz and 3.7 GHz. The design consists of a circular loop attached with 3 rectangular bars, and it is fed by a 50 Ω feed line. The circular loop in the antenna provides impedance matching. Generally, these electrically small antennas have narrow bandwidth. Here the antenna is fabricated on a polyimide substrate having a thickness of 0.1 mm, ε_r of 3.4 mm, and it occupies a size of 38 mm x 34 mm. Electrically small antenna is designed at 1.5 GHz, 3.7 GHz, and the parameters that are measured are S₁₁, VSWR, ka values, quality factor, and radiation patterns.

2023-05-16

PIER C

Vol. 133, 15-25, 2023

doi:10.2528/PIERC23022405

download: 18

5G Indoor Base Station Application: Low Profile Broadband Horizontally Polarized Omnidirectional Antenna

Shihao Wu Feng Shang

In this paper, a low profile horizontally polarized wideband omnidirectional antenna is presented, which consists of a simple single-layer dielectric substrate planar printing structure. The bottom of the substrate is loaded with six Vivaldi slits to achieve omnidirectional radiation. An equal-amplitude 1:6 power-division network is printed on the top of the substrate to provide a uniform feed. In addition, rectangular slots etched on each radiation element conduce to the enhancement of high-frequency gain and improvement of impedance matching. The antenna has 58.8% impedance bandwidth (2.8-5.13 GHz, VSWR<2) and low profile height of 0.009λ_min, and it is convenient to fix under the ceiling of buildings and could radiate well in indoor place. The radiation mode in the whole operating frequency band is stable, and the cross-polarization is less than -20 dB, which completely covers the 5G NR-n77/78/79 band.

2023-05-08

PIER C

Vol. 133, 1-13, 2023

doi:10.2528/PIERC23032606

download: 9

Nonuniform Structured Waveguides. WKB Approach

Mykola I. Ayzatsky

The results of the development of an approximate approach for describing structured waveguides, which can be considered as an analogue of the WKB method, are presented. This approach gives possibility to divide the electromagnetic field in structured waveguides with slow varying geometry into forward and backward components and simplify the analysis of the field characteristics, especially the phase distribution. The accuracy of this method was estimated by comparing the solution of the approximate system of equations with the solution of the general system of equations. For this, a special code was written that combines the proposed approach with the more accurate one developed earlier. For the case of fast damping of evanescent waves, a simple solution of the matrix equations is obtained. Based on this approach, the possibility of correcting the phase distribution in a chain of coupled resonators has been studied.