A Compact 4×4 Filtering Microstrip Patch Antenna Array With Dolph-Chebyshev Power Distribution

This paper proposes a compact $4 \times 4$ filtering microstrip patch antenna array with Dolph- Chebyshev distribution implemented by multilayer structure. The proposed antenna array features good filtering performance but contains no extra filtering parts in the feeding or the radiating element. The whole antenna array consists of four $1 \times 4$ antenna subarrays, each subarray is composed of four patch antennas which are coupled-fed by a single microstrip line. Inside the desired passband, by properly choosing the coupling area along the microstrip line, the patches are induced in-phase currents therefore achieving the excellent radiation characteristics. On the other hand, the four patches can’t be properly excited outside the passband which would enable radiation suppression performance. In order to implement a $4 \times 4$ filtering microstrip patch antenna array with low sidelobe level (SLL), four subarrays are combined and fed by Dolphy-Chebyshev excitation method. Finally, the proposed antenna array is implemented, fabricated and measured. The maximum measured gain in the passband is 14.7 dBi, and the radiation suppression outside the passband is better than 25 dB.