Circularly Polarized Antenna

Abstract

A dielectric resonator antenna was popular long time ago which normally used in microwave frequency. By varying the shape and the size of the dielectric resonator (irregular shape is also allowed), all the performance in Axial Ratio, Return Loss and Radiation Pattern will become different. In my project, a dual mode circularly polarized dielectric resonator antenna (DRA) was studied theoretically and experimentally. An operating frequency was designed to 3.4-3.7 GHz which is WIMAX band. This antenna was used in single feed line and placed on the ground plane .The size of the rectangular DRA has been tuned by using some mathematics equation. Thus, the operating frequency and dual mode pattern can be obtained in WIMAX region. Besides, by cutting the diagonal corner of the rectangular DRA, the circularly polarization was obtained. Also, in order to enhance return loss and axial ratio bandwidth, air gap and a metal strip were added on the top of the antenna. The designed antenna was simulated by software HFSS11 and measured by network analysis and the Satimo 3D Antenna Measurement System. The measured values are close to simulation results. The bandwidth of axial ratio which is less than 3dB is about 16.5%.