PIER Letters | PIER Journals

2024-03-29

PIER Letters

Vol. 118, 99-105, 2024

download: 162

A Dual-Mode Circular Antenna Array for Indoor Communication

Shen-Yun Wang , Meng-Ting Yang , Qing Zhang , Ling-Bing Kong and Wen Geyi

A circular antenna array with omnidirectional mode and 360° continuously directional beam-scanning mode operating in 5G indoor communication band is reported. The proposed circular antenna array is composed of 16 subarray elements, and each element consists of two back-to-back E-shaped patch antennas with a differential feeding network. The beam-scanning mode is achieved by controlling the exciting amplitudes and phases of consisting subarray elements, which is optimized by using the extended method of maximum power transmission efficiency, so as to guarantee the maximum possible gain value. The operating frequency of the circular array covers 3.3-3.6 GHz. The omnidirectional gain is about 4.7 dBi, while the directive gain reaches 16 dBi with 360° continuously beam-scanning performance and very slight gain fluctuation in the azimuth plane. The comparison with other state-of-the-art designs shows that the proposed circular array has both higher directional and omnidirectional gain values.

A Dual-mode Circular Antenna Array for Indoor Communication

2024-03-22

PIER Letters

Vol. 118, 93-98, 2024

doi:10.2528/PIERL23112206

download: 242

High-Performance Silicon Nitride Grating-Coupled SPR Sensors for Gas Detection and Biosensing

Mounir Bouras

Surface Plasmon Resonance (SPR) serves as a crucial optical technique in the realm of chemical sensing. Under specific conditions, the reflectivity of a thin metal film exhibits an exceptional sensitivity to optical changes in the medium on one side. In this investigation, we propose and simulate a plasmonic sensor incorporating a silicon nitride grating with Ag layers for the detection of solution and gas at an optical communication wavelength of 1550 nm. In both cases of the surface diffraction-grating, there is a notable enhancement in angular sensitivity compared to conventional prism-coupled configurations. Simulations, employing rigorous coupled wave analysis (RCWA), highlight that the suggested sensor, optimized in design parameters, offers notably superior sensitivity, a lower detection limit, and a higher figure of merit (FOM) than existing grating-based SPR sensors. This implies the potential realization of refractive index sensors with a high figure of merit through such streamlined and compact configurations.

High-performance Silicon Nitride Grating-coupled SPR Sensors for Gas Detection and Biosensing

2024-03-21

PIER Letters

Vol. 118, 85-92, 2024

doi:10.2528/PIERL24020202

download: 273

A Miniaturized and High-Gain Antipodal Vivaldi Antennas Using Directors

Islam M. Ibrahim , Mohamed Ismail Ahmed , Hala Mansour Abdelkader , Ahmed Jamal Abdullah Al-Gburi and Moataz. M. Elsherbini

In this paper, a miniaturized millimeter-wave (mm-wave) antipodal Vivaldi antenna (AVA) is proposed. The AVA structure is modeled using MWSCST2022 optimization tools. The AVA exhibits good impedance matching, high gain, and a small optimum size of 5x2.5x1.5 mm³, fabricated on an FR-4 substrate. An array of square and circular director units is modeled and loaded at the front and back of the AVA. The spacing between directors is studied and positioned at a tuned distance from the antenna for gain improvements and optimum radiation parameters. The AVA has an operating spectrum from 58 GHz up to 62 GHz. The finalized AVA, along with directors, obtained a high gain of 12.9 dBi with directors, while the AVA achieved 9.22 dBi without directors. The proposed antenna model is simulated and measured for short-range communications and imaging. The results of the modeling techniques and measurements agree well with each other.

A Miniaturized and High-gain Antipodal Vivaldi Antennas Using Directors

2024-03-20

PIER Letters

Vol. 118, 79-83, 2024

doi:10.2528/PIERL24021306

download: 285

A Modified Sparsified Nested Dissection Ordering Preconditioner for Discrete Exterior Calculus Solver Using Vector-Scalar Potentials

Boyuan Zhang and Weng Cho Chew

A broadband preconditioner based on a modified version of the sparsified nested dissection ordering (m-spaNDO) technique is proposed for the full wave discrete exterior calculus (DEC) A-Φformulation solver in electromagnetics. The matrix equation discretized by the DEC A-Φ solver is in general complex symmetric and indefinite. When conductive media and disparate mesh are involved, the DEC A-Φ matrix equation is ill-conditioned, and proper preconditioner must be utilized to accelerate iterative solver convergence. In this letter, an introduction to the DEC A-Φ solver is provided, followed by the implementation details of the m-spaNDO preconditioner. Numerical examples in this paper show that the proposed m-spaNDO preconditioner can effectively accelerate the convergence of iterative solvers in solving ill-conditioned problems. The m-spaNDO preconditioned DEC A-Φ solver has O(N logN) computational complexity and the efficiency of the preconditioner is independent of change in parameters such as frequency and conductivity in the problem, which indicates the broadband stable nature of the m-spaNDO preconditioner.

A Modified Sparsified Nested Dissection Ordering Preconditioner for Discrete Exterior Calculus Solver Using Vector-Scalar Potentials

2024-03-14

PIER Letters

Vol. 118, 71-78, 2024

doi:10.2528/PIERL23112406

download: 187

The Positive-Definite Stability Analysis for Marching-on-in-Time Schemes

Petrus Wilhelmus Nicolaas (Pieter) Van Diepen , Martijn Constant van Beurden and Roeland Johannes Dilz

The positive-definite stability analysis (PDSA) is presented as a technique complementary to the companion-matrix stability analysis (CMSA). The PDSA is used to analyze the stability of marching-on-in-time (MOT) schemes. The heart of the PDSA is formed by the analysis on particular linear combinations of interaction matrices from an MOT scheme, which are assumed to be real-valued. If these are all positive definite, then the PDSA guarantees the stability of the scheme. The PDSA can be of a lower complexity than the full CMSA. The construction of the PDSA is shown and applied to two numerical examples.

The Positive-definite Stability Analysis for Marching-on-in-time Schemes

2024-03-14

PIER Letters

Vol. 118, 63-69, 2024

doi:10.2528/PIERL24010304

download: 308

Design of an Octave-Multimode Hybrid Broadband High-Efficiency Power Amplifier

Zuqiang Zhang , Shiwei Zhao , Linsong Li , Longfei Zhou , Fei Zhao and Jialin Li

This paper discusses the challenges faced by existing power amplifier configurations in meeting the bandwidth requirements of modern communication technology while maintaining high efficiency due to the overlap of fundamental and harmonic frequencies. To address this issue, the paper proposes a matching method based on mode combination theory that utilizes the overlap of harmonic and fundamental impedance to simplify the design of broadband amplifiers. In this paper, a Chebyshev low-pass filter is used to control the higher harmonics instead of the conventional quarter-wavelength harmonic control network with a combination of harmonic impedances. The proposed method combines three modes of Resistive-Reactive class F^-1, class J, and class F power amplifiers, which can achieve high efficiency and octave frequency at the same time. The paper verifies the proposed method by designing and fabricating a multi-multiplier power amplifier with a drain efficiency of 61.8-73.9%, an operating bandwidth of 1.4-2.9 GHz, and a saturation output of 41.1-42.3 dBm. The amplifier also has a gain greater than 11.1-12.3 dBm, and at an output power of 36 dBm, the ACPR value is -32 to -33.1 dBc across the band.

2024-03-09

PIER Letters

Vol. 118, 55-61, 2024

doi:10.2528/PIERL23121402

download: 345

Broadband Bowtie-Based Log-Periodic Array Antenna via GIPD Process for 5G mm -Wave Applications

Jixuan Li , Zenghui Xiang , Xuan Chen , Mi Xu and Jinhui Li

In this paper, a broadband bowtie-based log-periodic array antenna is proposed and investigated for 5G millimeter wave (mm-wave) applications. Using a Glass Integrated Passive Device (GIPD) process, the proposed antenna is implemented on a high dielectric constant glass substrate. To address the directional radiation issues associated with the traditional straight connection, the proposed antenna uses a crisscross connection effect with carefully spaced three dipole elements. Furthermore, the use of bowtie-based dipole offers a wide bandwidth advantage. The study also examines the effects of changes in key parameters on critical antenna features. The feeding structure uses a combination of coplanar waveguide (CPW) and microstrip line to strip line. For demonstration, a prototype antenna is optimized, fabricated and measured. The measurement results show that the 10 dB impedance bandwidth of the proposed antenna is from 21.5 to 36.1 GHz, and the gain is higher than 5.63 dBi.

Broadband Bowtie-based Log-periodic Array Antenna via GIPD Process for 5G mm-Wave Applications

2024-03-07

PIER Letters

Vol. 118, 47-53, 2024

doi:10.2528/PIERL24020111

download: 290

A Dual-Port Pattern Diversity Antenna Based on FHMSIW Technology for Omnidirectional Coverage

Chu Zhang and Yangjun Ou

A dual-port pattern diversity antenna is proposed in this letter for omnidirectional coverage. Two end-fire radiating beams are realized based on a two-element magnetic currents array. A folded half-mode substrate integrated waveguide (FHMSIW) is introduced to ensure that the distance between the two equivalent magnetic current radiation sources is about λ₀/4 (λ₀ is the wavelength in free space). When the two elements are driven by signals with a 90˚ or -90˚ phase difference, two end-fire radiation patterns with opposite directions can be realized. A prototype working at 2.425 GHz is fabricated and tested, achieving two independent end-fire radiation beams with a maximum gain of 4.3 dBi. Compared with conventional omnidirectional antennas, this work can effectively improve the gain of omnidirectional coverage based on a very compact structure.

A Dual-port Pattern Diversity Antenna Based on FHMSIW Technology for Omnidirectional Coverage

2024-03-04

PIER Letters

Vol. 118, 41-46, 2024

doi:10.2528/PIERL24010801

download: 266

Design of Dual-Band FPD with High Selectivity

Tiantian Zhang , Lei Chen , Meng Liu , Jinyi Liu and Min Wang

In this brief, a dual-band filtering power divider (FPD) with high selectivity and independently controllable passbands is designed. The proposed FPD consists of asymmetric folded F-type resonators (AFFRs) and quarter-wavelength three parallel-coupled lines (TPCLs). The center frequencies of the dual bands can be determined by adjusting the physical lengths of AFFRs. Meanwhile, TPCLs can increase the transmission paths and introduce multiple transmission zeros (TZs) to achieve high selectivity. For demonstration, the proposed FPD is designed, fabricated, and measured. The center frequencies are 2.59/3.63 GHz with the 3-dB fractional bandwidths (FBWs) of 12.95% and 7.88%, and the isolation between port 2 and port 3 is better than 12.56/21.03 dB. The minimum insertion losses are better than 0.54/0.32 dB in each passband. The simulated results are compared with measured ones, and good agreement is realized.

Design of Dual-band FPD with High Selectivity

2024-03-04

PIER Letters

Vol. 118, 33-39, 2024

doi:10.2528/PIERL23121503

download: 365

Radio-Frequency Energy Harvester for a Hybrid Power Supply with Constant Voltage Output to a Water Meter

Junlin Mi , Ruinan Fan , Jianwei Jing , Liping Yan and Changjun Liu

This manuscript proposes a hybrid energy harvest and management system to manage harvested ambient thermal and radio frequency (RF) energy and provide constant voltage for an electronic water meter. It mainly includes an antenna, a rectifier, thermoelectric generators (TEGs), and an energy management circuit. The antenna harvests the ambient RF power, and the rectifier converts it to DC power. The harvested RF and thermal powers are stored in a capacitor and managed by an FEH710 energy management circuit to power an electronic water meter. Eight thermoelectric generators convert thermal energy into DC power. The proposed hybrid energy harvesting and management system has been evaluated by simulation and measurement. The antenna's reflection coefficient and peak gain at 2.45 GHz are -30 dB and 3.6 dBi, respectively. The rectifier's measured RF-DC power conversion efficiency (PCE) is 66.7% at 0 dBm. As a demonstration, a commercial electronic water meter worksstably by the harvested ambient RF and thermal energy. The proposed hybrid energy harvesting system is expected to find potential practical applications for the Internet of Things (IoT) in environments with RF radiation coverage and temperature gradients.

Radio-frequency Energy Harvester for a Hybrid Power Supply with Constant Voltage Output to a Water Meter

2024-02-29

PIER Letters

Vol. 118, 27-31, 2024

doi:10.2528/PIERL24010307

download: 325

Millimeter-Wave Dual-Frequency Dual-Polarized Circular Airy OAM Beams by Tensor Holographic Impedance Metasurface

Hui-Fen Huang and Yingjing Ma

In this paper, analytical formulas for tensor holographic impedance metasurface (THIMS) are presented to generate circularly polarized (CP) circular Airy orbital angular momentum (OAM) multibeams with flexibly independent control of the beam direction, polarization and OAM mode. As an example, a millimeter-wave THIMS is designed to generate CP circular Airy OAM dual beams: Beam-I: (θ1 = 0, φ1 = 0, LHCP, l = +1, 36 GHz), Beam-II: (θ2 = 0, φ2 = 0, RHCP, l = 0, 30 GHz). To the knowledge of the authors, for the first time, the THIMS generates circular Airy beams. Compared with the published metasurface on Airy beam, the created THIMS has the following advantages simultaneously: dual frequencies, dual CP, small size 30λ₀ at 30 GHz, high conversion efficiency (CE) (above 40%), long nondiffractive distance (ND) (up to 134.4λ₀), high OAM purity (above 89%), co-modulation for polarization, beam direction and OAM mode. The generated circular Airy OAM beams can be used in near-field scenarios such as high-efficiency wireless power transmission (WPT), high-capacity communication systems, and high-resolution imaging.

Millimeter-wave Dual-frequency Dual-polarized Circular Airy OAM Beams by Tensor Holographic Impedance Metasurface

2024-02-23

PIER Letters

Vol. 118, 21-26, 2024

doi:10.2528/PIERL24010303

download: 317

A Single-Layer Filtering Slot Antenna Based on Circular SIW Cavity

Yinghang Chen , Xuehui Guan , Xianling Liang , Baoping Ren and Shaopeng Wan

A low profile and high selectivity filtering slot antenna based on circular substrate integrated waveguide (SIW) cavity is presented. The proposed antenna is originated from a circular SIW cavity operating at its TM₀₁₀ mode. A cruciform slot is integrated on the top surface of the cavity, and the cavity is then split into four quarter-mode cavity resonators. In this aspect, the four similar quarter-TM₀₁₀ modes will be generated by the compact structure. By amalgamating four similar modes into a single-band, the bandwidth of antenna is widened. Based on the structure, a filtering slot antenna with central frequency of 8 GHz and bandwidth of 5.6% is designed and fabricated. Measured results agree well with the simulated ones. In addition, two radiation nulls are produced at the edges of the passband, and the selectivity in the transition band is enhanced greatly.

A Single-layer Filtering Slot Antenna Based on Circular SIW Cavity

2024-02-17

PIER Letters

Vol. 118, 15-20, 2024

doi:10.2528/PIERL24010403

download: 359

A Miniaturized High-Selectivity Filter by Embedding Nested U-Shape Resonators in SIW

Xiaohei Yan , Wenjing Mu , Minjie Guo , Xiumei Huang and Haiyan Zeng

A substrate-integrated waveguide (SIW) miniaturization filter is proposed, which features high attenuation characteristics, effectively reduces filter loss and size, and improves frequency selectivity. The filter is miniaturized using the evanescent-mode theory and embeds a nested U-shaped resonator in the upper metal surface of the SIW. The proposed filter's equivalent circuit structure incorporates two LC parallel resonant loops with resistance characteristics that can, in turn, create two transmission zeros in the filter's stopband to enhance its selectivity. The filter has an effective size of only 0.39λ_g×0.23λ_g with a center frequency of 2.5 GHz. The -3 dB bandwidth measures 120 MHz, while the relative bandwidth is 4.8%. The insertion loss is -0.6 dB in the passband, and the return loss is more than 25 dB. Out-of-band rejection exceeds 40 dB in the range of 2.9~4.4 GHz. The measured and simulated results agree well. The filter offers benefits in terms of high rejection, miniaturization, and low insertion loss. It can be implemented in 5G (sub-6 GHz) wireless communication systems.

A Miniaturized High-selectivity Filter by Embedding Nested U-shape Resonators in SIW

2024-02-14

PIER Letters

Vol. 118, 9-14, 2024

doi:10.2528/PIERL23112901

download: 368

DOA Estimation of Quasi-Stationary Signals Based on a Separated Generalized Nested Array

Jing Zhao , Sheng Liu , Decheng Wu and Cheng Zeng

This paper proposes a sparse array consisting of two separated generalized nested arrays. The unit element-spacing of each generalized nested array can be adjusted to multiple half-wavelengths of the incident signal. By adjusting the element-spacing, the mutual coupling effect can be greatly reduced. For this array, a direction of arrival (DOA) estimation method of quasi-stationary signals has also been proposed. By using the received signals of the separated generalized nested array, a signal subspace is obtained. Then, this subspace is filled into a higher-order signal subspace to avoid angle ambiguity. Using the higher-order signal subspace, DOAs of all signals can be estimated by spectral peak search. Simulation results show that the proposed separated generalized nested array has better than the conventional nested array performance in DOA estimation.

DOA Estimation of Quasi-stationary Signals Based on a Separated Generalized Nested Array

2024-02-14

PIER Letters

Vol. 118, 1-7, 2024

doi:10.2528/PIERL23100503

download: 346

Opportunities in Antenna Development by Using Distilled Water

Benigno Rodríguez Díaz and Leonardo Barboni Morales

This paper presents some opportunities in the development of antennas when using Distilled Water (DW) as a dielectric with high relative electrical permittivity (ε_r(DW) = 80). By embedding an antenna in DW, the electrical growth of the antenna is achieved without significantly increasing its physical size. In other words, the antenna will resonate at frequencies lower than those to whom it originally resonated. It was also found that the antennas developed through this technique are usually multiband antennas, offering various resonance frequencies at frequencies lower than the original ones. Finally, the change in radiation patterns was also verified through the use of this technique that allows beamforming to be carried out by varying the size and shape of the DW block. The development of more efficient antennas has a direct impact on the energy consumption of wireless systems, which represents an effective contribution to climate change mitigation, the reason that the improvement of antennas is a very important research area.