A method for shaped reflector antenna design

A method is developed for shaping a single reflector antenna to achieve a specific contour coverage in the far field. The method is iterative and converges to an optimal surface when the last optimized surface does not vary significantly from the previous iteration. An offset parabola is specified as the initial surface. It is important to choose a reasonable initial geometry, since the final solution is dependent on this starting surface. The technique involves computing the aperture field distribution for each reflector surface using the finite element method, and carrying out a phase only optimization for the far field coverage using the power matrix method. The finite element method accounts for the curvature of the surface in computing the aperture field, and the power matrix method is an efficient way of computing far field patterns for an array of identical elements as the excitation coefficients of these elements change for each iteration.