E-Plane Radiation Pattern Decoupled Microstrip Antenna Pair Using Embedded Mushroom Element

In this paper, a simple E-plane radiation pattern decoupling structure is proposed for a pair of closely-placed, mirror-arranged microstrip antennas. Two mushroom-shaped elements, each surrounded by a capacitive air gap, function as inductor-capacitor (LC) series resonators, and are embedded into the adjacent radiation edges of the square patch pair without requiring extra space. By employing this method, the coupling current can be effectively shorted, and the E-field interference from the coupled antenna can be suppressed, therefore, the radiation patterns are significantly restored. Simulated results illustrate that the port isolations between two antennas with a center spacing of 0.32 ?_? are improved to over 26 dB within the operating bandwidth of 2.62 2.78 GHz and reach a maximum value of 49.5 dB. Moreover, the undistorted radiation patterns are obtained. The proposed decoupling method possesses a single-layer structure and space-saving properties, which are beneficial for low-cost fabrication and easy integration into dimension-limited antenna applications.