Miniaturization of Wullenweber antenna

A method for miniaturizing a Wullenweber antenna is presented. If we intend to reduce the dimension of the Wullenweber antenna, we must reduce the number of elements in the /spl phi/-direction so as not to make the adjacent elements too close. In this situation, the beam becomes broader and the beam angular increment corresponding to the element spacing becomes greater. This means that there is a deterioration in the azimuth resolution and in the angular precision. It is shown that the angular precision can be improved by employing a beam phase tilting technique using the phase shifters which have been installed to form the beams which are steered with an angular increment corresponding to the element spacing. The azimuth resolution can be improved by increasing the lower limit for the monopulse condition keeping the null level of the difference pattern sufficiently low, which can be realized by controlling the amplitude illumination by using attenuators.