Design of circularly polarized slot antennas

Abstract

Satellite technologies have been found impact on our daily life. Therefore, there is a demand of circularly polarized (CP) antenna in the current market. In my project, circularly polarized (CP) high gain slot antennas for operation from 1.5GHz-1.7GHz are proposed firstly. Such antennas achieve high gain characteristics. It is capable of providing wide axial ratio bandwidth by using single probe feed and reasonable return loss bandwidth. The most advantage of the proposed antennas is that single element antenna can yield a gain as high as a traditional antenna array. Others advantages such as low cost, simple architecture and easy for fabrication can be performed. For some applications, wide coverage antennas are demanded. To fulfill such requirement, low-gain and wide-beamwidth CP antennas are studied secondly. By bending the slots from the straight into L-shaped, the gain can be lowered and larger beam width can be achieved. Also, the L-shaped slot is bent again to C-shaped to achieve larger beam width. Besides, beamwidth can be increased by adjusting the height of ground reflector below the patch and cutting slots on a metallic cavity instead of a metallic plate. Details of the proposed antenna designs are described, and experimental results for CP performances are presented and discussed.