PIER Letters | PIER Journals

2026-11-11 Latest Published

Design of a Compact Filtering Antenna with Wide Bandwidth and Wide Stopband Suppression
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By Xinwei Chen Xingwang Xie Jinrong Su Guorui Han Wenmei Zhang Runbo Ma

Progress In Electromagnetics Research Letters, Vol. 133, 22-28, 2026

DOI:10.2528/PIERL26092204 | Google Scholar

Abstract

This paper presents a compact broadband filtering antenna with wide stopband suppression performance. A quarter-wavelength shorted stub is integrated into the feeding structure to excite an additional low-frequency resonant mode and introduce a controllable transmission zero. Meanwhile, a parasitic patch is loaded to generate high-frequency resonant modes and upper-band transmission zeros, further expanding the impedance bandwidth. In addition, the hybrid integration of a dumbbell-shaped defected ground structure (DGS) and an open-circuited feed stub effectively suppresses high-order harmonic radiation, achieving wide stopband suppression. To clarify the multi-resonance coupling principle and inherent filtering mechanism of the integrated antenna configuration, a corresponding equivalent circuit model is established and analyzed. Measured results verify that the proposed filtering antenna achieves a broad impedance bandwidth of 19.01%, covering 3.76-4.55 GHz, with a peak realized gain of 6.35 dBi. Remarkably, the designed antenna achieves a wide stopband suppression range up to 3.07f₀ in the -10 dBi gain suppression level. The proposed filtering antenna is suitable for application in the extended frequency bands of 5G-Advanced.

2026-11-11

PIER Letters

Vol. 133, 22-28, 2026

DOI:10.2528/PIERL26092204

download: 8

Design of a Compact Filtering Antenna with Wide Bandwidth and Wide Stopband Suppression

Xinwei Chen, Xingwang Xie, Jinrong Su, Guorui Han, Wenmei Zhang and Runbo Ma

2026-11-11

PIER Letters

Vol. 133, 15-21, 2026

DOI:10.2528/PIERL26090802

download: 4

Line-of-Sight Pre-Analysis for Efficient Bayesian Optimization of Indoor Transmitter Placement

Sejin Kim, Seungchan Lee, In-Sik Choi and Seongwon Oh

Optimizing indoor transmitter placement via 3D ray-tracing is computationally intensive. To overcome this limitation, this study proposes an efficient method that integrates geometry-informed line-of-sight (LoS) pre-analysis with Bayesian optimization (BO). A boundary-line-based 2D occupancy grid is generated from CAD drawings to prevent the loss of vertical structures, and LoS scores for all 770 Tx candidate locations are obtained in approximately 3 s, including all preprocessing of the CAD geometry, without ray-tracing simulation. Spatially distributed candidates with high LoS scores are selected as initial points for BO to improve search efficiency and surrogate model accuracy. Simulation results in a smart factory environment show that the proposed method avoids local optima pitfalls of randomly initialized BO and reaches the global optimum in only 37 evaluations (5.9 h). This achieved a 33% reduction in search time compared to Particle swarm optimization (PSO) and up to 69% compared to the grey wolf optimizer (GWO) while finding the identical global optimum, demonstrating superior efficiency for computationally expensive propagation environments.

Line-of-Sight Pre-Analysis for Efficient Bayesian Optimization of Indoor Transmitter Placement

2026-11-09

PIER Letters

Vol. 133, 6-14, 2026

DOI:10.2528/PIERL26081702

download: 6

A DGS Decoupling Method for PIFA Antennas Based on Common-Mode/Differential-Mode Analysis

Tao Yang and Yafei Wang

To address mutual coupling between antennas in MIMO antenna systems, this paper proposes a decoupling method for a MIMO PIFA using a defected ground structure (DGS) based on common-mode/differential-mode (CM/DM) theory. We use the CM/DM response relationship as an explicit design criterion to guide DGS structure evolution and the selection of critical geometric parameters. Simulation results show that the proposed PIFA MIMO antenna achieves more than 20 dB of port isolation over the 3.8-3.9 GHz band, with a peak isolation of 57 dB, while maintaining good impedance matching. Moreover, the measured results of the fabricated prototype agree well with the simulated results, further validating the effectiveness of the proposed method.

A DGS Decoupling Method for PIFA Antennas Based on Common-Mode/Differential-Mode Analysis

2026-11-09

PIER Letters

Vol. 133, 1-5, 2026

DOI:10.2528/PIERL26071103

download: 6

Displacement of the Field of a Current Source Located near a Layered Stack Composed of Single-Negative Layers

Leonid Pazynin, Kostyantyn Sirenko and Vadym Pazynin

A rigorous analytical solution is obtained for two-dimensional boundary value problems describing E-polarized fields of a current source located near two- and three-layer stacks composed of single-negative layers. Conditions for complete tunneling of the source field into the half-space behind the multilayer stacks are formulated. It is rigorously demonstrated that such structures exhibit the previously predicted effect of ideal image displacement.