Dual frequency and dual circular polarization microstrip nonresonant array pin-fed from a radial line

A new type of a dual frequency and dual circular polarization multilayer microstrip nonresonant antenna array for satellite communication is presented. The microstrip radiating elements in the array are arranged in concentric circles and fed through pins embedded in a radial line. The radial line is excited through a probe at its center. The microstrip array exhibits a dual frequency band of operation, low side-lobes in the radiation pattern, and high radiation efficiency (more than 65%) for both polarizations. The microstrip element has been designed using commercial software based on the method of finite integral time domain algorithm, and the feed network has been designed by a theoretical analysis. A prototype of the array has been built and tested. The agreement between the measured and numerical results is satisfactory.