Microwave Imaging using an Impulse Signal

It is shown how the EM field over an object plane can be synthesised from a time domain record of the far-field radiation off the axis of symmetry. Two off-axis observations are sufficient to synthesise a two-dimensional distribution and the spatial resolution attainable (independent of distance) depends on the time variation of the source field. The experimental results use an antenna aperture as the object field but the method is intended for radar targets. A new technique of waveform processing in the time domain avoids singularities which can arise in frequency domain processing.