Experimental study of dielectric loaded planar antenna fed by waveguide network

Gain enhancement of an antenna is achieved by loading of a rectangular parallelpiped or circular cylindrical dielectric in front of a source with the ground plane. The dielectric loaded antennas with a diameter d=(1/spl sim/3)/spl lambda//sub 0/ (/spl lambda//sub 0/: wavelength in free space) have the mixed properties of dielectric covered antennas, rod antennas and lens antennas. We reported a high gain planar array antenna for DBS, whose element antenna was a circularly polarized microstrip patch loaded by a dielectric, but the aperture efficiency of this antenna was limited in terms of the conductor and the radiation losses of the microstrip lines. The element antenna loaded by a dielectric has such a high gain that the grating lobe can be decreased sufficiently even if the element spacing in the array is wider than the wavelength in free space. Therefore it is expected that the parallel feeding by the waveguide network may be feasible and then we can develop a high efficient and broad frequency bandwidth array antenna. This paper reports experimental results of the dielectric loaded planar antenna fed by a waveguide network with 16 element radiators. This has a gain of 26.5 dBi at 12.7 GHz with an aperture efficiency of 96 %.<>