Circularly polarized microstrip antenna with dual-CPW feed

The authors demonstrate a new design of using a dual-CPW feed for achieving wideband circular polarization (CP) radiation. The dual-CPW feed consists of two orthogonally oriented CPW feed lines of a quarter guided wavelength difference in length and is connected to a Wilkinson power divider implemented by CPWs. The complete CPW feed network is printed on the ground plane of the patch substrate. And owing to the good isolation between two outputs of the Wilkinson power divider, good equal input powers and 90/spl deg/ phase difference for the dual-CPW feed can be obtained and the proposed design can thus be expected to have wideband CP radiation. The proposed design incorporating the use of a circular radiating patch and an inexpensive FR4 microwave substrate is implemented, and measured results are presented and discussed.