Novel Dual-Frequency Microstrip Antenna With Narrow Half-Ring and Half-Circular Patch

A novel dual-frequency microstrip antenna is presented. The dual-frequency is generated through a half-ring structure and a half-circular patch element. The half-ring is narrower than the conventional ring antenna, and the parameters that decide the resonant frequency of the antenna are studied. Simulation and measurement results show that the proposed antenna works at 0.9 and 1.8 GHz.