Wideband circularly polarized square slot antenna with an annular patch

Abstract

ABSTRACT This article presents a novel and compact circularly polarized square slot antenna (CPSSA) that operates across 2.93–11.43 GHz with an impedance bandwidth of 118% for VSWR ≤ 2. This makes the antenna feasible for UWB applications requiring high data rate transmission. The antenna with an annular radiation patch is fed through a coplanar waveguide and includes two inverted‐L shaped ground arms at two opposite corners of the slot to excite two orthogonal resonant modes for circular‐polarization (CP) radiation. A semicircular stub is embedded in the feed‐line to enhance its impedance bandwidth. The antenna exhibits CP bandwidth of 22.2% across 4.87–6.09 GHz, which incorporates the WLAN band. In addition, the antenna has a significantly smaller volume of 25 × 25 × 0.8 mm 3 . The measured and simulated results confirm the usefulness of the antenna for practical applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:229–233, 2014