Microwave imaging of multiple metallic cylinders using shape functions

A novel technique for microwave imaging of multiple metallic cylinders with E/sub z/ incident fields is presented. The novelty stems from the definition of shape functions applied to discrete subscatterers, and the technique is more versatile for general multiple metallic inverse scattering problems. In the forward problem, the scattering volume is discretized on a regular grid. Then, a set of binary shape functions is applied to the cylindrical subscatterer locations to represent the scatterers. Here, the subscatterer fields are approximated by cylindrical harmonics and the boundary conditions are enforced on each subscatterer by the T-matrix method. The resulting matrix equation can be inverted for the subscatterer harmonic amplitudes. Then, in the inverse problem, the metallic scatterers are approximated by analog shape functions and an iterative linearized optimization is done. Monochromatic superresolution is achieved to a scale of 0.1 lambda for single scatterers; multiple scatterers can be resolved at a separation of 0.42 lambda .<>