Characterization of dual‐polarized monostatic patch antennas for full‐duplex applications

Abstract

This paper presents the characterization of two different dual‐polarized monostatic (shared radiator) antennas. As an example, the design and implementation of two dual‐polarized 2.4 GHz patch antennas are presented in this paper for in‐band full‐duplex (IBFD) or single‐channel full‐duplex (SCFD) wireless applications. Both the antennas use orthogonal feeding ports but differ in feeding structures. The effect of the shape of radiating patch (square shape vs circular shape) on interport RF isolation characteristics of dual‐polarized patch antenna is studied along with the effect of the feeding position on interport isolation of dual‐polarized square‐shaped patch with thin quarter‐wave microstrip feeds. The simulated interport isolation results for monostatic and bistatic dual‐polarized antennas are compared. The simulation results show the effect of slot length, slot width, stub length, size of patch, and feed line on intended frequency of operation for the single‐port slot‐coupled patch antenna. Finally, the performance of two dual‐polarized implemented antennas is analyzed by comparing the measured interport isolation (S12) results at a required operating frequency around 2.4 GHz. The implemented antenna with thin co‐planar quarter‐wave microstrip feeds provides 43 dB interport isolation, while the dual‐port slot‐coupled IBFD antenna has 70 dB interport isolation at the center frequency. The slot fed antenna provides > 55 dB port to port isolation within 10 dB return loss bandwidth of 50 MHz. The dimensions of the implemented antennas are 68 mm x 68 mm x 1.6 mm and 68 mm × 68 mm × 3.2 mm, respectively. Due to the use of high‐loss FR‐4, the radiation efficiencies and gains of both antennas are around 60% and 4 dBi, respectively. The novelty and contribution of this work are the design, implementation, and detailed analysis of two dual‐polarized compact antennas for full‐duplex applications.