Dual frequency and dual circular polarization microstrip array fed from a radial waveguide

A new type of a dual frequency and dual circular polarization array fed from a radial waveguide through wire pins is presented. It uses a new multilayer radiating element. in the array, the radiating elements are distributed on concentric rings and the radial waveguide is fed through a wire probe at its center. The suggested array antenna permits us to reduce the sidelobe level in the radiation pattern. An 8-ring prototype of an array operating in two frequency bands 11.7-12.2 GHz with right-hand circular polarization (RHCP) and 14-14.5 GHz with left-hand circular polarization (LHCP) has been built and tested. The agreement between the computed and the test results is satisfactory.