Dual-Polarized High-Gain Microstrip Antenna for MIMO Wireless Communication Systems

In this paper, a method of achieving dual-polarized high-gain microstrip antenna for MIMO wireless communication applications is proposed utilizing the slot-loaded higher order mode. By loading half-wavelength slots on electric field nulls of ordinary microstrip antenna operating at higher order mode, equivalent in-phase magnetic current array can be constructed within a single low-profile cavity using simple feed technique. To verify the proposed method, a dual-polarized TM50-mode microstrip antenna with a maximum measured gain of 10.9 dBi is presented firstly, using single-layered substrate and a pair of single feeds. Further, a dual-polarized high-gain magnetic current array with a pair of differential feeds is demonstrated utilizing TM90 mode, achieving a maximum measured gain of 15.5 dBi. Moreover, the low envelop correlation coefficient indicates the good diversity performance of the proposed antennas. The proposed method has the merits of low profile, high isolation and simple feeding, with promising usage in MIMO and diversity applications.