Design of a Circularly-Polarized Miniaturized Microstrip Annular Ring Antenna

A design approach to obtain a miniaturization, semi-circular, slotted annular ring antenna with circularly-polarized (CP) radiation is presented in this paper. Firstly, the antenna is miniaturized on the basis of a traditional annular ring antenna, which can reduce the overall transverse size by nearly 50%. After that, good CP radiation characteristics is well achieved under a single-point feed by simply loading a horizontal sector slot on the annular ring. Simulation results show that the proposed antenna has a −10dB impedance bandwidth of 11.3% and an axial ratio bandwidth of 3.8%.