Synthesis of satellite footprint patterns from time-modulated planar arrays with very low dynamic range ratios

An efficient pattern synthesis approach has been developed for the synthesis of satellite footprint patterns using time-modulated planar arrays. The approach can be used to effectively control both the ripples in the coverage zone and the sidelobe levels, due to the adoption of time-modulated antenna arrays. The optimized time sequences and element excitations are obtained by the method based on a combination of a differential evolution strategy (DES) and a modified 2D Woodward-Lawson method. Normally, planar array synthesis is rather time consuming, partly due to the inherently large number of optimization variables and partly due to the fact that the calculation of fitness function is also time consuming. A fast computation approach based on the 2D fast Fourier transform (FFT) is thus applied in the DES for the planar array pattern computation. Several representative examples are presented to show the flexibility and effectiveness of the proposed approach. Copyright (C) 2008 John Wiley & Sons, Ltd.