A Four-Channel Millimeter-Wave On-Line Imaging Method

Abstract

Microwave imaging is achieved by a method, which uses several homodyne receivers, positioned along a linear aperture in order to evaluate the incident angles of incoming wavefronts. The sampled values of the field distribution along the aperture are submitted to a Fourier transfrom, giving the directions of incidence. As this method is used for short range applications, the reduction of the sensitivity imposed by the homo- dyne principle can be tolerated, avoiding expensive IF circuitry. Considering moving objects, the changes of the incident field distribution is well described by the doppler effect. This means, that only low frequency data have to be processed and the evaluation of the data can be done on-line by a desk-top calculator. As distance information is obtained by additional switching between two adjacent frequencies, two dimensional images can be demonstrated on-line on the screen of a desk-top calculator.