Decoupling circuit design for dual-band and dual-polarized microstrip antenna

Abstract

This paper presents a decoupling design of dual-band and dual-polarized microstrip antenna. The proposed antenna uses four angle-adjustable $\lambda/4$ ground stubs to cancel out the E-plane coupling between two adjacent elements. Furthermore, the dumbbell-shaped defected ground structure is inserted to reduce the H-plane coupling. The prototype antenna was fabricated in this work where edge-to-edge separation of the antenna elements were kept at $0.072\lambda_{0}$. Experimental results verify that the proposed design effectively suppresses the mutual coupling of the dual-band and dual-polarized antenna. The isolation of the antenna at 5.2 GHz and 6 GHz is increased by 18.1 dB and 20.8 dB, respectively.