CIRCULARLY-POLARIZED DIELECTRIC-LOADED PLANAR ANTENNA EXCITED BY THE PARALLEL FEEDING WAVE-GUIDE NETWORK

The new receiving planar array antenna for DBS (Diredt Broadcasting Sa tellite) is proposed, The element antenna is a short waveguide apertur e mounted in the ground plane, loaded with the dielectric and the pola rizers, and excited through its side wall by another feeding rectangul ar waveguide, The gain of the element antenna loaded with a dielectric is so high that the grating lobes can be reduced sufficiently even if the element spacing in the array is wider than the wavelength in free space, Therefore we can reduce the number of the array elements, and the parallel feeding by the low loss waveguide network can be feasible to get an excellent planar array antenna. This paper describes the ex perimental results of several kinds of the circularly polarized dielec tric-loaded element antennas and the planar antennas fed by the wavegu ide network, In 12GHz band the planar antenna with 64- element radiato rs has the maximum gain of 31.9dBi with the aperture efficiency of 94. 7%, the 1dB-down frequency bandwidth of the gain of about 800MHz (6.7% for center frequency 11.85GHz), and the frequency bandwidth of the ax ial ratio less than 1dB of 850MHz (7.2%).