PIER Letters | PIER Journals

2024-09-11

PIER Letters

Vol. 122, 87-92, 2024

download: 60

Bio-Electromagnetic Safety Assessment of Wireless Charging Environment for Electric Vehicles

Haoran Zheng and Xiaohe Zhao

Wireless power charging technology has been developed rapidly and is extensively utilized for electric vehicle wireless charging due to its numerous over plug-in charging. The electromagnetic bio-safety of the human body in charging environment has become a significant public concern. To address this issue, this paper employes the finite element analysis method to assess the electromagnetic safety of crucial organs in a typical charging environment. Firstly, human-vehicle models in various typical postures were constructed in COMSOL, and the spatial distribution of electromagnetic fields in the critical organs was calculated in a 7.7 kW, 85 kHz charging environment. Subsequently, the electromagnetic radiation dose of each organ was calculated and compared with the ICNIRP standards. The results indicated that the electromagnetic radiation dose received by different organs is influenced by both the electromagnetic parameters and position of the organs. When the human body is positioned flat in the car, the electromagnetic radiation exposure to various organs is at its highest. Additionally, the maximum radiation dose for each organ is significantly below ICNIRP standard in a low-power wireless charging environment, supporting the commercial adoption of wireless charging technology for electric vehicles.

Bio-electromagnetic Safety Assessment of Wireless Charging Environment for Electric Vehicles

2024-09-09

PIER Letters

Vol. 122, 81-86, 2024

doi:10.2528/PIERL23041406

download: 47

Multi-Band Band-Pass Filter with Independently Controlled Asymmetric Dual-Band Response Based on Metacell

Shobha Hugar , Jambunath S. Baligar , Veerendra Dakulagi and Kashipura Manjanaik Vanitha

The key challenges in the design of multi-band filters are realizing highly independent, controlled asymmetric-wide and narrow dual-band response. To address these challenges, this paper proposes the design and development of a dual-band band-pass filter (BPF) with highly independent, controlled wide and narrow band responses. The proposed filter is constructed using only two resonator structures, asymmetric step impedance resonator (A-SIR) and metacell. The wide and narrow band responses are independent and are controlled independently by impedance ratio (R) and the number of cells (N) in metacell structure, respectively. Additionally quasistatic circuit model of the metacell is used to analyze independently controlled narrow passband response. The prototype of the filter is fabricated, and the simulation results are validated through experimental measurements.

Multi-Band Band-Pass Filter with Independently Controlled Asymmetric Dual-band Response Based on Metacell

2024-08-28

PIER Letters

Vol. 122, 75-80, 2024

doi:10.2528/PIERL23102104

download: 132

Deviation Analysis of Multiport VNA Hardware Specification-Related Nonideality

Nan Sun , Liang Ren , Zhi-Tao Yang , Ming Shen and Hong-Wei Deng

In this paper, the deviation generated by actual multiport vector network analyzer (MVNA) hardware specification is derived. Based on the error flowchart of the n-port VNA, the generalized matrix expression of the raw scattering parameters for each error term is solved by introducing the generalized node method. Combined with incremental method, the generalized matrix expression of the final relative scattering parameter measurement deviation is calculated after ignoring the infinitesimals above the second order. Thus, the method of variable controlling is applied to make difference so that the deviation associated with every error term can be obtained. The validness and effectiveness of this method are verified by utilizing Agilent N5230C to measure a 20 dB direction coupler. The data is processed with an algorithm in MATLAB.

Deviation Analysis of Multiport VNA Hardware Specification-related Nonideality

2024-08-27

PIER Letters

Vol. 122, 67-74, 2024

doi:10.2528/PIERL24040101

download: 136

Study on the Two-Load Transmission Characteristics of a WPT System with Double Transmitting Coils

Suqi Liu , Xueying Yan and Yuping Liu

It is expensive that each consuming power equipment needs to equip a separate wireless power charger. In addition, obtaining constant output power and high transfer efficiency in large coupling variation ranges is challenging. In this study, the two-load transmission characteristics of a WPT system with double transmitting coils are studied. The circuit model of the two-load WPT system is first developed, and the transmission characteristics are studied. The two-load WPT system achieving constant output power and transmission efficiency is then studied. Finally, the two-load WPT experimental system is designed. This system can achieve self-adjusting impedance compensation. Moreover, the constant output power and transmission efficiency are achieved in each receiver, where their fluctuations are less than 5%. Furthermore, the utilization of the charger is improved by more than 8% due to the two receivers. This topology can provide a solution for practical application problems, such as the two-load wireless charger of the vehicle mobile phone.

Study on the Two-load Transmission Characteristics of a WPT System with Double Transmitting Coils

2024-08-21

PIER Letters

Vol. 122, 59-65, 2024

doi:10.2528/PIERL24062701

download: 220

Multi-Band 3D Printed Frequency Selective Surface for RF Shielding Applications

Deepika Singh , Rana Pratap Yadav and Hemdutt Joshi

This paper presents the design and development of 3D printed multi-band frequency selective surface (FSS) for RF shielding applications. The developed FSS significantly rejects the frequency at Wi-Fi, Wi-Max and ISM/WiMax bands. The FSS has been fabricated using a 3D printed ABS substrate and metalized with a copper paint as per design. Its unit cell consists of three independent sub-geometries in which two are mostly like a concentric square loop that encircles the third one, i.e., modified Jerusalem structure. All of these sub-geometries are individually designed for the different rejection bands where their combination is optimized as a unit cell of FSS. The designed unit cell rejects the Wi-Fi, Wi-Max and ISM/WiMax centered at 2.45 GHz, 3.5 GHz and 5.8 GHz with attenuation level more than 35dB. The developed FSS is a prototype of RF shielding structure to be utilized for the fabrication of an interference-free test chamber which isolates the Wi-Fi, Wi-Max and ISM/WiMax interference. The design of FSS is very simple and can be printed in large scale for the development of shielding applications.

Multi-band 3D Printed Frequency Selective Surface for RF Shielding Applications

2024-08-19

PIER Letters

Vol. 122, 53-58, 2024

doi:10.2528/PIERL24071004

download: 231

A Wideband High-Isolated Dual-Polarized Magnetoelectric Dipole Antenna for 4G/5G Communications

Yanhong Xu , Minling Wang , Xiaochao Yang , Can Cui , Xuhui Fan , Tingting Bai and Jianqiang Hou

A highly-isolated dual-polarized magnetoelectric (ME) dipole antenna is proposed in this letter, where a modified cross-shaped differentially-feeding structure is designed to realize dual-linear polarizations (LPs). To broaden the bandwidth of the differentially-driven ME dipole antenna, a pair of L-shaped branches are loaded on the positions where a triangle is cut out of each patch to introduce a new resonant frequency at the upper frequency region. Meanwhile, a two-stepped structure is added to each of the four ports of the cross-shaped differentially-feeding structure to improve the impedance matching characteristic of the antenna. In this way, the 10 dB bandwidth is improved from 64.9% (1.54-3.02 GHz) to 83.5% (1.52-3.70 GHz), i.e., 28.7% bandwidth enhancement is achieved. A prototype is fabricated and measured. The results show that the proposed antenna can achieve a high differential port-to-port isolation of better than 38 dB, cross-polarization level (CRPL) lower than -25 dB, and peak gain up to 10.5 dBi.

A Wideband High-isolated Dual-polarized Magnetoelectric Dipole Antenna for 4G/5G Communications

2024-08-18

PIER Letters

Vol. 122, 45-51, 2024

doi:10.2528/PIERL24061104

download: 252

A Compact Low-Loss Single-Layer Vialess Diplexer Based on Complementary Microstrip Spiral Resonators for Satellite Communications

Giacomo Giannetti , Stefano Maddio and Stefano Selleri

The design of a compact low-loss diplexer based on complementary microstrip spiral resonators is described. The resonant elements are two: one is low-pass (channel A) and the other is passband (channel B). The low-pass element is composed of spirals departing from a circle, whereas the passband element is composed of spirals etched on a circle. The former element is novel and has been extensively analyzed here. These elements are connected using a star nonresonant Y-junction to form a single-layer vialess diplexer. As an example, a diplexer working at 0.87 and 2.0 GHz for satellite communications is manufactured and tested. The measured data show an insertion loss equal to 0.58 dB (0.66 dB) for channel A (B). The return loss exceeds 15 dB for both channels, and the dimensions are 0.129λ × 0.265λ ≈ 0.0343λ².

A Compact Low-loss Single-layer Vialess Diplexer Based on Complementary Microstrip Spiral Resonators for Satellite Communications

2024-08-14

PIER Letters

Vol. 122, 37-44, 2024

doi:10.2528/PIERL24052402

download: 229

A Miniaturized Tag Antenna Based on Meandered Line Technique for UHF Radio Frequency Identification Applications

El Mustapha Louragli , Younes El Hachimi , Sudipta Das , Tanvir Islam , Boddapati Taraka Phani Madhav and Abdelmajid Farchi

The current paper describes a compact, long-reading-range tag antenna for radio frequency identification (RFID) applications in the UHF (ultra-high frequency) band, operating at 915 MHz. The antenna's miniaturized design is achieved through the utilization of the meandering line technique. A T-matching structure matches the chip impedance to that of the antenna. Polytetrafluoroethylene, or PTFE, is used as the substrate for fabrication. The UHF tag's physical dimensions are 44.4 × 14.4 × 0.8 mm³. This antenna was first designed, simulated and then optimized by software CST-MWS (Computer Simulation Technology-Microwave Studio) before being fabri-cated. The Measured reflection coefficient at 915.5 MHz is approximately -24 dB, exhibiting a bandwidth of 7,9 MHz (911.5 MHz-919.4 MHz). The proposed tag is shown to have gain of 1.56 dB and radiation efficiency of 90% at the resonant frequency of 915 MHz. Its long-reading-range at 915 MHz is roughly 18.41 m, for an EIRP of 4 W. The measured results closely align with the simulated ones.

A Miniaturized Tag Antenna Based on Meandered Line Technique for UHF Radio Frequency Identification Applications

2024-08-07

PIER Letters

Vol. 122, 29-35, 2024

doi:10.2528/PIERL24061601

download: 296

Conformal Angularly Stable Quadband Frequency Selective Surface for EMI Shielding

Naveena Meka and Krishnan Shambavi

This article presents a miniaturized dual layer angularly stable quadband frequency selective surface (FSS) for shielding applications. The shield consists of four metallic square rings on a thin FR4 substrate of relative permittivity 4.4 and thickness 0.5 mm with two rings on top layer and other two rings in the bottom layer. The dimension of the shielding unit cell is 0.2λ × 0.2λ, for the lowest frequency. These shields have been analyzed in both planar and conformal configurations. The equivalent circuit models as well as analytical model are determined. The shield exhibits quad band band stop characteristics with transmission zeros at 5 GHz (4.3-5.8 GHz), 6.6 GHz (6.3-6.8 GHz), 8.3 GHz (7-8.8 GHz) and 15 GHz (11-17 GHz). These bands find their application in shielding upper WLAN band, sub 6 GHz 5G band C/Ku band for satellite communication. The proposed FSS prototype is fabricated and tested for shield effectiveness in an anechoic chamber. The proposed FSS design offers stable angular response up to 60˚ for planar and geometry. Simulated and measured transmission coefficients are in good agreement and hence well suited for shielding applications. As the structure is fourfold symmetric, it exhibits polarization insensitive and angular stability in all four bands.

Conformal Angularly Stable Quadband Frequency Selective Surface for EMI Shielding

2024-08-03

PIER Letters

Vol. 122, 21-28, 2024

doi:10.2528/PIERL24041404

download: 298

Pattern Compensation of a Planar Phased Array with Centre Elements Phase Malfunctioning Using a Genetic Algorithm

Raja Aasim Bin Saleem , Arslan Ali Shah , Hina Munsif , Ali Imram Najam , Shahid Khattak and Irfanullah

A phase-only and amplitude-phase genetic algorithm (GA) has been investigated to restore the array pattern of a 4 × 2 planar array in the presence of centre-elements phase malfunctioning. A single and double adjacent antenna elements are considered for phase malfunctioning. The new array weights for functioning antenna elements are computed with GA to restore the value of array peak gain and sidelobe level (SLL). The simulation results, which are verified with measurements, indicated that complete recovery of array pattern without SLL constraint in the presence of malfunctioning elements was possible with the phase-only GA weights. It is shown that the uncorrected pattern can also be compensated for main beam scanning with phase-only GA weights. However, pattern compensation with SLL constraint is not possible using the phase-only GA weights. Therefore, amplitude-phase GA weights are estimated to restore the peak gain and the desired SLL simultaneously at the cost of widening the main beam. A prototype of X-band 4 × 2 microstrip patch array controlled through X-band phaser evaluation boards was used in the in-house anechoic chamber measurements facility to validate the full-wave HFSS simulation results.

Pattern Compensation of a Planar Phased Array with Centre Elements Phase Malfunctioning Using a Genetic Algorithm

2024-07-27

PIER Letters

Vol. 122, 15-20, 2024

doi:10.2528/PIERL24061003

download: 333

Low Profile UHF-RFID Reader Antenna with High Front-to-Back Ratio

Safia Chenaoui , Lila Mouffok and Sami Hebib

In this paper, a low profile UHF-RFID reader antenna with high front-to-back ratio is presented. The antenna consists of a probe-fed U-slot rectangular patch antenna loaded with a slotted AMC reflector, formed of 2 × 2 unit cells. By incorporating the AMC reflector, a compact profile height of 0.049λ (λ is the wavelength at 910 MHz) is achieved with high gain and front-to-back ratio. The proposed reader antenna is fabricated and measured. The experimental results are similar to those predicted by electromagnetic simulation and validate the proper operation of the antenna across the entire UHF-RFID band (860-960 MHz). Moreover, the realized prototype exhibits a measured realized gain and a front-to-back ratio (F/B) greater than 5 dBi and 24 dB, respectively. The proposed design offers the advantages of low profile, high gain and F/B ratio, rendering it suitable for compact RFID readers.

2024-07-21

PIER Letters

Vol. 122, 9-14, 2024

doi:10.2528/PIERL24061101

download: 383

Mode Control of Slotline Resonator and Its Application to the Design of Balanced BPF with Ultra-Wide Stopband

Jia-Qi Wang and Feng Wei

In this paper, a mode control technology of a slotline resonator is proposed and utilized to guide the design of the slotline resonator. With this method, characteristic modes generated by the slotline resonator are more controllable. With characteristic mode analysis, which is the core of this technology, the desired and unwanted modes of the slotline resonator are easy to be analyzed, controlled, and further used to expand the stopband bandwidth. By applying this technology, a multi-mode slotline resonator with a T-shaped coupling structure (MMSR-T) is proposed by modifying a multi-mode slotline resonator (MMSR), and its unwanted modes out of the passband are more controllable without influencing the expected modes in the passband. Based on the proposed MMSR-T, a balanced bandpass filter (BPF) is proposed, which consists of a U-shaped microstrip/slotline transition as the input/output structure, a T-shaped slotline feeding structure as a feeding terminal, and MMSR-T as the filtering unit. Through the mode analysis and design of MMSR-T, ultra-wide differential-mode (DM) stopband, high common-mode (CM) suppression, and high DM selectivity are obtained in this design. The measured results agree well with the theoretical predictions and simulated results. The effects of mode control technology on stopband extension are proven.

Mode Control of Slotline Resonator and Its Application to the Design of Balanced BPF with Ultra-wide Stopband

2024-07-20

PIER Letters

Vol. 122, 1-7, 2024

doi:10.2528/PIERL24060501

download: 334

Square-Coupled Topological Filter with an Ideal Rectangular Coefficient Facilitated by Dual-Cavity Single-Mode and Single-Cavity Dual-Mode SIW Resonators

Xiaohei Yan and Wenjing Mu

In order to achieve miniaturization and high performance in microwave filters, this paper proposes two double-layer bandpass filters with different structures, both equivalent to square-coupled topologies. These filters employ dual-cavity single-mode and single-cavity dual-mode substrate-integrated waveguide resonators. In this configuration, the upper layer comprises two single-mode resonators connected to the input and output feed lines, while the lower layer contains dual-mode resonators coupled to the upper layer's single-mode resonators through two slots on the middle metal layer. A comprehensive analysis is conducted on the impact of primary parameters on filter characteristics and transmission zero positions. The second filter is fabricated and tested, yielding results consistent with simulation outcomes. The center frequency of the filter is 4.77 GHz, with a 3 dB bandwidth of 0.16 GHz (relative bandwidth: 3.35%). Additionally, its rectangularity coefficient at 10 dB approximately equals one, an ideal value for practical applications.