Wideband Patch Antenna Using Multiple Parasitic Patches and Its Array Application With Mutual Coupling Reduction

A dual-layer patch antenna using multiple parasitic patches for the bandwidth enhancement is presented. Two additional resonances can be obtained with the help of the parasitic patches of the antenna. Consequently, a wide impedance bandwidth of 17% (|S11| <; -10 dB) can be achieved. Then, without the increase of the antenna array footprint, the combinations of two decoupling techniques (i.e., metalized via walls and short-circuited stepped-impedance structures as the neutralized networks) are adopted for mutual coupling reduction when the antenna element is extended to 2 x 1, 2 x 2, and even 4 x 4 array applications. To validate the design idea, a 2 x 2 antenna array is fabricated and tested, whose measured isolations between any two feeding ports are better than 28 dB within the frequency range of 3-4 GHz. The measured peak gain fluctuates from 12.6 to 13.6 dBi within the 10-dB impedance band of 3.35-3.95 GHz, and the crosspolarization levels in both the Eand H-planes are lower than -38 dB at the boresight direction.