Microwave holographic imaging method with improved resolution

A multifrequency holographic microwave imaging method with high resolving capability in both azimuth and range directions, is described. The method incorporates a synthetic aperture approach in pulse radar systems, originally designed for the pulse-echo imaging, in order to improve azimuth resolution. The imaging technique places no constraint on the waveform of a transmitted signal in use and allows the three-dimensional imaging. This paper develops 1) the general formula, which describes the relation between the transmitted and received signals, based on Kirchhoff diffraction theory, 2) a test function, which is the kernel of a linear operation for producing object images from received signals, and 3) a filter design technique for compressing the durations and suppressing the sidelobe levels of received signals. Numerical image reconstructions are presented for demonstrating high resolution capability of the method.