Compact and high isolated microstrip patch antenna system for full-duplex/MIMO applications

This paper presents a two-port microstrip patch antenna system with compact size and high isolation for full-duplex and multiple-input-multiple-output (MIMO) applications. The proposed miniaturization approach is to employ compact microstrip patch antenna and decoupling network as well. Here, two quarter-wavelength patch antennas are arranged in the H-plane coupled configuration with element spacing of about 0.008 λ at the center operating frequency. Besides, a defected ground structure is chosen as the decoupling network, which doesn't require any additional space and contributes to significantly reducing the overall antenna dimensions. The final antenna design with compact size of 0.49 λ × 0.37 λ × 0.01 λ has operating band from 2.45 to 2.48 GHz, in which isolation is better than 30 dB and the maximum isolation is 42 dB. Besides, the proposed antenna also achieved comparable gain of 3.8 dBi and good diversity performance. In comparison with other related works, the proposed design has smallest overall size with extremely small element spacing while obtaining comparable isolation enhancement.