A circular polarized self tracking L band array with high bandwidth and scan beamwidth for inmarsat BGAN applications

This paper presents a 4×5 element antenna array for applications such as Inmarsat BGAN. This array addresses an important phenomenon which appears to have been little reported in the literature. This is the degradation of circular polarisation characteristics when a CP array is steered electronically. The design of this array presents significant challenges, as not only does it have to maintain a high quality of CP when scanning up to ±40°, but also has to do this over an 8.5% frequency coverage of 1.525 to 1.66 GHz. The resulting array was able to fulfil these requirements, with element sequential rotation being employed to further enhance the CP characteristics.