A Low-Profile Decoupling Slot-Strip Array for 2 × 2 Microstrip Antenna

Two-dimensional antennas provide additional variables that can be used to control and shape the pattern, and widely used in engineering applications include tracking radar, communications, direction finding and many others. However, the reduced mutual coupling becomes more complex due to the mode and strength of the mutual coupling field between sani adjacent elements are different. In this paper, a low-profile decoupling slot-strip array (DSSA) for 2 × 2 microstrip antenna is proposed. The DSSA consists of a slot array etched on the ground plane and a strip array printed on the radiation patches plane. The band-stop effect of the slot array decreases the mutual coupling of both H-plane and D-plane. Meanwhile, the coupling current generated by the induced current on strip array can cancel the coupling current generated by excited current, which can significantly improve the E-plane isolation Additionally, the scattering parameters of other three types of antenna which have the different relative positions of feeding ports are also discussed. To verify the proposed viewpoint, a 2 × 2 antenna with the DSSA is modeled and manufactured. The experimental results demonstrate that a considerable mutual coupling reduction of 33.2 dB for H-plane, 28.5 dB for E-plane, and 24.1 dB for D-plane is achieved while 10 dB bandwidth for S11 remains almost unchanged. Fortunately, the experimental results are in good agreement with the simulation results, which confirms that the DSSA has an excellent promising application in two-dimensional antenna.