High selectivity and efficiency differential dual-polarized filtering patch antenna

This article presented a high selectivity and efficiency differential dual-polarized filtering patch antenna. A square driven patch together with a square parasitic patch are utilized to obtain a filtering performance. By loading an upper parasitic patch with a cross slot in the center, a radiation null is introduced on the high side of the passband. Two pairs of slots with the same size of folded U-shape are symmetrically etched on the diagonal of the driven patch, generating another radiation null on the low side of the passband. Thus, the antenna can achieve a good filtering gain response with two radiation nulls, realizing high selectivity. Additionally, as no extra filtering circuit is utilized, high radiation efficiency is also acquired. An antenna prototype is processed and measured, showing a bandwidth of 7.4%, high isolation of 32 dB, an antenna peak gain of 9 dBi and an efficiency of -0.29 dB in the center frequency.