A low-complexity compact dual-polarized patch antenna with high isolation and low cross-polarization for in-band full-duplex applications

This paper proposes a simple design of a dual-polarized microstrip patch antenna featuring compact dimensions, low cross-polarization, and high port isolation, specifically designed for full-duplex wireless applications. The antenna is implemented on a single-layer substrate, and size reduction is achieved through a capacitive loading technique. Additionally, capacitive loading also contributes to increasing polarization purity by suppressing cross-polarization radiation. A fabricated prototype with an overall size of 0.18λ × 0.18λ × 0.03λ at 5.6 GHz demonstrates stable performance across the frequency range of 5.53–5.62 GHz. Within this band, the antenna attains an isolation level exceeding 38 dB, a maximum broadside gain of approximately 4.3 dBi, and low cross-polarization radiation of less than $$-40$$ dB. Compared to other related compact dual-polarized designs, the proposed antenna exhibits the best performance in terms of isolation and cross-polarization suppression, featuring a compact and simple structure.