Design of a broadband circularly-polarized lens antenna with a linearly polarized feeder

This paper presents a novel broadband thin lens antenna applied to circularly-polarized applications. The lens is composed of four identical novel conducting surfaces sandwiching three identical dielectric layers. The novel design is able to generate transmission phases of over 300° in two orthogonal directions separately, which can be applied to design lens antennas for applications of single, dual and circular polarizations. In addition, the design also includes advantages of a compact size, ease of fabricating and mounting, and a low cost. The numerical results demonstrate broad bandwidths of the 3-dB axial ratio and 1-dB gain, together with stable far-field radiation patterns.