Microstrip Patch Array Filtenna Based on Array Decoupling Surface Structure

In this letter, a broadband microstrip patch array filtenna based on array decoupling surface (ADS) structure is proposed. The ADS unit comprises a split-ring resonator housing a patch resonator. Positioned above the array antenna, the ADS structure serves to eliminate coupled waves, thereby enhancing isolation and generating transmission zeros beyond the operational bandwidth to improve out-of-band suppression. The operational principle of the ADS structure is elucidated through equivalent circuits and electromagnetic simulation. The proposed configuration is implemented in a 1 × 2 patch array featuring “X”-shaped slot feeding. Measurement results demonstrate exceptional performance, including isolation exceeding 25 dB, a broad operational frequency band spanning 12.82 GHz to 15.67 GHz (20%), and two transmission zeros positioned respectively in the upper and lower stopbands. These attributes make the structure a promising candidate for practical multiple-input–multiple-output (MIMO) antenna applications.