A new method based on the differential evolution (DE) algorithm is proposed for antenna-array pattern synthesis with prescribed nulls. The array excitation amplitudes are the only controlling parameters, and the objectives are to synthesize array patterns with nulls imposed on directions of interferences while keeping the sidelobe levels (SLLs) below prescribed levels. Many factors such as the excitation dynamic range ratio, null depth level, null width, and SLLs are taken into account in the synthesis. Simulation results of several typical problems are compared with published results to illustrate the effectiveness of the proposed method.

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This paper reports results obtained by linear and nonlinear iterative scalar inversion of experimental electromagnetic scattering data sets for different targets. The applied inversion schemes are a linear diffraction tomography algorithm and three nonlinear iterative methods. Two domain integral equation based methods, namely a modified gradient in field algorithm and a contrast source inversion method, are used. The third method is a real-coded genetic algorithm based on a boundary integral equation formulation. Inversion results are presented and compared for dielectric targets (penetrable scatterers) and metallic targets (perfect scatterers) using measurements for the transverse magnetic polarization case acquired in an anechoic chamber.

A simple and fast single channel passive millimeter wave (PMMW) imaging system for public security check is presented in this paper. It distinguishes itself with traditional ones by an innovative scanning mechanism. Indoor experiments against human body with or without concealed items in clothes show that imaging could be completed in 3 s with angular resolution of about 0.7°. In addition, its field of view (FOV) is adjustable according to the size of actual target.