A new kind of circular polarized slotted waveguide array antenna

We present a new waveguide slot configuration able to radiate a circular polarization with a very low axial ratio. This configuration is mainly intended as a circularly polarized element to be used in an array. Both left-hand and right-hand circular polarization can be independently obtained and therefore this configuration could be used to realize a polarization agile antenna. The design approach is based on the analysis and optimization of the aperture fields of one radiation unit cell in order to produce good performance of circular polarization. An array of eight elements with uniform spacing is realized in Ka-band with a gain of 10.67 dB. The grating lobes arising due to large inter element spacing are suppressed by loading the waveguide with dielectric. And the relative AR bandwidth is about 9.2%.