Corner-fed dual-band circularly polarised antenna

A slot-coupled dual-band circularly polarised (CP) antenna is presented for 1.575 and 2.45 GHz bands. The antenna is composed of a split-patch surrounded by a split-ring. The slits can be lined-up toward the centre of the antenna to generate dual CP bands with opposite senses (left-hand and right-hand waves). To generate dual CP bands with the same sense, the slits on the patch is located orthogonal to the slits on the ring. In the coupled feed, the slot is a square in shape and is corner-coupled to a microstrip line. The lengths of the slits are tuned for good CP operations at both bands. Good match is obtained on both bands by adding stubs to the feeding microstrip line.