A Reconfigurable Radiation Pattern Microstrip Patch Antenna with High Mode Purity

A single-layer, dual-mode circular microstrip patch antenna is presented to achieve reconfigurable radiation patterns with high mode purity. The broadside radiation pattern is achieved by a central circular patch, whereas conical radiation pattern is realized through a concentric shorted ring patch. With the simultaneous excitation of the two operating modes, the proposed antenna can generate self-scanning and self-nulling radiation patterns. The proposed antenna was fabricated and tested. Simulated and measured results show that the antenna produces stable broadside and conical radiation patterns with high mode purity at the design frequency of 10 GHz.