Highly sensitive measurements with a lens-focused reflectometer

A lens-focused microwave reflectometer that offers exceptional sensitivity and very wide bandwidth is described. The system produces a well confined spot focus and, with the prescribed calibration procedure, gives effective directivity approaching 70 dB. Applications include dielectric constant measurements and scanned imaging of bodies. Precision of +or-1 dB is demonstrated for measurements, in X-band, at the -50 dB level. >