A Low-Cost Wideband Circularly Polarized Slot Array With Integrated Feeding Network and Reduced Height

This letter proposes a wideband unidirectional circularly polarized (CP) slot array with a truly planar structure, which integrates the feeding network on a single substrate. The height of the array is reduced by half compared to traditional arrays with a reflector. Four parasitic slots are etched at the edges of the ground plane to improve the gain performance when the height is reduced. The measured results show that the bandwidths (BWs) for impedance, axial ratio (AR), and gain are all more than 23%, and these three bandwidths almost cover the same frequency band. The proposed array has a good unidirectional pattern and can be used in base-station applications.