For the applications of X-band satellite-earth communications, high gain and
circularly polarized arrays of cavity-backed slot (CBS) antenna are eligible
choice. The aim of this work is to present analysis of the linear, rectangular and
circularly polarized arrays of CBS antenna. Two configurations of linear arrays
are investigated to produce a directive beam with high gain and beam-steering
capability. The variation of the gain of linear arrays with the number of elements,
element spacing, and phase of the applied signal are considered. Rectangular
arrays are used to produce linear polarization with high gain, high front-to-back
ratio and low side-lobe level. Two configurations of circularly polarized arrays
are investigated: cross-shaped and square-shaped arrays. Both configurations
can produce right-hand circular polarization (RHCP) as well as left-hand
circular polarization (LHCP) by proper setting of excitation phase for each
element in the array. The finite-difference time-domain (FDTD) method is used
to analyze the characteristics of each of the array element including the input
impedance, S-parameters, radiation patterns, gain and axial ratio. The results of
the circularly polarized arrays show that the proposed array configurations seem
very promising and useful for geostationary satellite applications.