Microstrip Open-Slot Antenna With Broadband Circular Polarization and Impedance Bandwidth

A design with broadband and circularly polarized radiation from an open-slot antenna has been successfully demonstrated in this communication. The proposed antenna, which consists of an open slot and a patch-protruded feeding topology, provides a large bandwidth, which covers the operation bandwidth of a satellite digital audio radio service system. The open slot is formed by an L-shape conducted strip asymmetrically connected at the edge of the ground plane. After optimization, the final structure, which measured 3-dB axial-ratio bandwidth for the left-hand circular polarization is 2.47 GHz (76%) from 2.00 to 4.47 GHz; meanwhile, the measured impedance bandwidth of a reflection coefficient less than -10 dB ranges from 1.22 to 5.97 GHz, a 4.75-GHz impedance bandwidth (133%).