A broadband circularly polarized slot antenna with a compact microstrip to CPW transition

摘要

A simple structure of broadband circularly polarized slot antenna based on coplanarrnwaveguide (CPW) feeding is proposed in this article. To obtain circular polarizationrnwith a single feed, a transition from microstrip to CPW is designed to excite the evenrnand odd modes of the CPW simultaneously. By adjusting the relative position andrndimensions of the two circular patches introduced at the end of microstrip line andrnCPW, a 90° phase difference between two modes can be produced. When the twornmodes are coupled into the wide slot antenna, broadband circular polarization operationrncan be realized. The 10-dB reflection coefficient bandwidth of the proposedrnantenna is 88.2% (2.49-6.42 GHz) and 3-dB AR bandwidth attains 50% (2.72-rn4.49 GHz).