Aperture-coupled circularly polarized F-slot microstrip antenna

A compact, aperture-coupled, circularly polarized F-slot microstrip antenna is proposed. The F-slot is embedded in the square microstrip patch and fed using an aperture-coupled feeding structure. The proposed antenna has a 4.87% (2.40-2.52 GHz) 3 dB AR (axial ratio) bandwidth with a 14.4% 10 dB return loss bandwidth. The gain within the usable bandwidth remains relatively constant at 6.0 dBic with a ±0.5 dB variation and a peak gain is 6.2 dBic at 2.42 GHz,. The antenna ground plane size and foam substrate thickness represent about 53.3 and 7% of its wavelength at the operating frequency of 2.46 GHz, respectively. The 3 dB AR beamwidth is >90°. The patch size of the proposed antenna is reduced by 22.7% compared with a conventional square patch antenna.