A Single-Layer Single-Patch Dual-Polarized High-Gain Cross-Shaped Microstrip Patch Antenna

This letter presents a single-layer, single-patch, dual-polarized, high-gain microstrip patch antenna. The design starts with a cross-shaped microstrip patch antenna, which has the property of high gain. An antenna array model is derived to give an explanation of the mechanism and the theoretical limitations. Moreover, the center part of the cross-shaped patch is removed to reduce the sidelobe level. Then, a dual-polarized high gain antenna is designed based on the modified cross-shaped patch. In addition, a cross-shaped strip is introduced to improve isolation. Finally, a prototype is fabricated and measured to prove our idea. The measurements reveal that the proposed antenna has a 10 dB impedance bandwidth of 1.8% from 4.74 to 4.83 GHz, with a peak realized gain of 12.47 dBi at 4.77 GHz. The isolation of two ports is higher than 24.8 dB within the passband. The overall size of the proposed antenna is only 1.44λ ₀ $ \times $ 1.44λ ₀ $ \times $ 0.024λ _0.