Bandwidth enhancement of circularly polarised slot global navigation satellite systems antenna using an integrated filter‐antenna approach

Abstract

Abstract:A technique to enhance the bandwidth of a circularly polarised antenna using the filter‐antenna design approach is presented. The design relies on adding a resonator coupled to the radiation element—an L‐shaped slot antenna in the case of global navigation satellite systems. This change in the feeding structure broadens both the impedance and the axial ratio (AR) bandwidths and allows more design flexibility. Compared with a reference L‐shaped slot antenna with a conventional feed, the proposed antenna design achieves a doubling of the impedance matching bandwidth from 19% to 41% over the frequency range from 1.2 to 1.81 GHz and a wider AR bandwidth from 35% to 44.5% in the range from 1.17 to 1.84 GHz. The AR bandwidth covers the entire impedance bandwidth. The effect of a metal reflector on antenna performance is also investigated and discussed.