Synthesis methods of array antenna excitation laws

Standard numerical optimization methods become very computational time consuming when dealing with synthesis of array antenna excitation laws, especially when number of elements exceeds a few tenths. Array antenna designer needs a fast and efficient synthesis tool, since the design phase implies several reoptimizations within the definition phase, in order to satisfy tradeoffs on antagonistic requirements : performances, size, cost,… We propose the use of an efficient, from the computational time point of view, and secured, from the convergence point of view, synthesis method illustrated by two examples. The optimized solution satisfies a sta-tionarity condition, which leads to steady solutions in frequency but also with regard to errors (manufacturing, …). Based on analytical calculus performed before any numerical resolution 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 being performed on a pc. Two theoretical applications are presented and for each of them a computed example is also shown; moreover possible extensions are considered.