LAUSR

A compact broadband circularly polarised (CP) aperture antenna is proposed. In order to broaden the CP bandwidth, a pair of perturbation slots is introduced to generate a higher order mode (quasi-TE31) for CP radiation. With three resonant modes working simultaneously a wider CP bandwidth is obtained. Besides, with some modifications to the ground plane, the antenna is miniaturised while keeping its wideband CP performance. The measured CP working bandwidth is 76.6% (2.9–6.5 GHz) with the antenna size of 43 mm × 43 mm, which means a 71% CP bandwidth increment and a 47% size reduction compared with the original CP aperture antenna.