A Broadband Circularly Polarized Wide-Slot Antenna With a Miniaturized Footprint

Abstract

This letter presents a novel and simple feeding technique for exciting orthogonal components in a wide-slot antenna. In this technique, a rectangular bracket-shape parasitic strip is placed at the open end of the straight microstrip line to excite the fundamental horizontal and vertical components of the circular polarization (CP). The proposed technique-when employed in conjunction with the asymmetrical geometry of coplanar waveguide and a protruded stub from the ground plane-permits for maintaining axial ratio (AR) below 3 dB within a wide range in the C-band as well as a compact footprint of the antenna. All geometry parameters of the antenna are adjusted through rigorous EM-driven optimization to obtain the best performance in terms of footprint, impedance matching, and AR bandwidth (ARBW). The size of the proposed antenna is only 27 mm × 28.8 mm. The structure features a 62% impedance bandwidth (3.6-6.85 GHz) and ARBW of approximately 49% (3.6-5.93 GHz) with the average realized gain of 3.3 dB within the CP operating band. Numerical results are validated experimentally. A close agreement between simulation and measurement results has been observed.