Design of tilted beam circularly polarized antenna for CP-SAR sensor onboard UAV

In this paper, a tilted beam circularly polarized antenna is designed. This L-band antenna is designed to be mounted on the bottom of unmanned aerial vehicle (UAV) for circularly polarized synthetic aperture radar (CP-SAR) sensor. The antenna is composed of four elliptical elements and a proximity-feeding network. By arranging the phases different to each element, the main beam of radiation can be tilted to proposed angle for a side looking radar. The phase shifting is obtained by varying the length of the antenna feed line. A method of moment (MoM) is employed for optimizing the design and achieving a good circular polarization at the targeted frequency (1.27 GHz). The tilted beam and axial ratio indicate the antenna is promising for the CP-SAR.