SYNTHESIS METHODS OF ARRAY ANTENNA EXCITATION LAWS

Standard numerical optimization methods become very computational time consuming when dealing with synthesis of array antenna excitation law s, especially when number of elements exceeds a few tenths. Array ante nna designer needs a fast and efficient synthesis tool, since the desi gn phase implies several reoptimizations within the definition phase, in order to satisfy trade-offs on antagonistic requirements : performa nces, size, cost,... We propose the use of an efficient, from the comp utational time point of view, and secured, from the convergence point of view, synthesis method illustrated by two examples. The optimized s olution satisfies a stationarity condition, which leads so steady solu tions in frequency but also with regard to errors (manufacturing,...). Based on analytical calculus performed before any numerical resolutio n and together with the use of fast Fourier transform algorithms, this method leads to reduced optimization times (in the order of a minute) for arrays of some tenths up to some hundred feeds, computations bein g performed on a pc. Two theoretical applications are presented and fo r each of them a computed example is also shown; moreover possible ext ensions are considered.