Array thinning in phased arrays using dual mode horns

The authors investigate a new concept in array design, where the level of the grating lobes is controlled by the element pattern. For the array elements circular horns are selected. In standard arrays these horns operate in the TE/sub 11/ mode and beam scanning is achieved fully by element phasing. In the present case, each array element operates in the first two TE/sub 11/ and TE/sub 21/ modes and the element pattern is shaped to place a null in the direction of the grating lobes. Thus, the interelement spacing can be increased beyond that of normal arrays, without a serious pattern degradation due to the appearance of the grating lobes. Also, the array elements in the present study are assumed to be circularly polarized.<>