Waveguide slot array with CSC2 theta (dot) COS theta pattern

A planar array of longitudinal shunt slots in rectangular waveguides has been designed to produce a CSC sup 2 theta . COS theta patern in the E-plane and -22-dB sidelobes in the H-plane. The array operates at 15 GHz. The choice of E-plane amplitude and phase distribution, to synthesize the CSC sup 2 theta COS theta pattern shape over the sector 8 deg to 50 deg below broadside, involved a tradeof study. A technique reported perturbing the roots on a Schelfunoff unit circle to obtain the disired pattern shape was used Twelve roots were perturbed in a systematic way to obtain an optimum amplitude distribution with accompanying phase angles. A method to spread the resultant E-plane distribution and the H-plane Taylor distribution over a circular aperture is described. The mutual coupling between elements is considered for the design. The predicted results show good agreement with measurements.