Multilayer Dual-polarized Microstrip Antenna Design by Topology Optimization with Enhanced Bandwidth

2026-08-06

AI Summary

This work addresses the inherent limitations of dual-polarized microstrip antennas—narrow bandwidth and insufficient port isolation—by introducing, for the first time, a density-based topology optimization approach applied to a double-layer FR4 substrate. The method co-optimizes copper distribution across both layers to simultaneously enhance port matching, achieve high isolation (>40 dB), and maintain desirable far-field dual-polarization characteristics, yielding a well-balanced performance within an approximately 10% impedance bandwidth. A prototype antenna operating at 5.7 GHz was fabricated and validated through both electromagnetic simulation and experimental measurement, with excellent agreement between simulated and measured results. This demonstrates the effectiveness and novelty of the proposed multilayer topology optimization strategy for dual-polarized antenna design.

Abstract

Dual-polarized (DP) microstrip antennas are utilized in wireless systems for efficient data transmission. However, their bandwidth is typically very limited. In this contribution, we propose to design DP microstrip antennas with enhanced bandwidth using a density-based topology optimization approach. We formulate an optimization problem that simultaneously accounts for feeding port matching, the ports' isolation, and far-field dual-polarized performance. To enhance the bandwidth, we employ an FR4 stack-up, in which the copper on two layers is optimized simultaneously. We present two antenna designs operating around 5.7 GHz, which show a compromise in performance between a high isolation (more than 40 dB) and enhanced impedance bandwidth (around 10%). The optimized designs are experimentally validated, showing an excellent agreement between the simulated and measured performance.

Problem

• dual-polarized microstrip antenna
• bandwidth limitation
• wireless systems
• impedance bandwidth
• port isolation

Innovation

• topology optimization
• dual-polarized antenna
• enhanced bandwidth
• multilayer microstrip
• port isolation