Broadband circularly polarized antenna with circular sot and separated L-probes

This paper presents a circular slot antenna that generates wideband circular polarization. The horizontal and vertical components of the L-shaped probe are separated and fabricated on the front and back side of the substrate. This incorporates a capacitance effect in the antenna by which the phase difference between the two orthogonal components to generate circular polarization can be controlled to 90°. The effect of attaching stubs in the slot is proposed to improve the axial ratio bandwidth to a large extent. The measured Sll<;-10dB bandwidth is 48.95% and the axial ratio bandwidth <; 3 dB is 44.78%. The overlapped bandwidth is 41.18% in measurement and the antenna also shows a good cross polarization discrimination of > 15 dB in a wide azimuth range. A good agreement between the simulated and measured result is also achieved.