Centimetre resolution time domain reflectometry using ultra-short millimetre wave pulses

We present a technique for making time domain reflectometry (TDR) measurements of mm-wave systems using sub-nanosecond 94GHz pulses which yields distance resolutions of a few centimetres. Pulses as short as 115ps are generated using a novel switched 7.8 to 94GHz frequency multiplier chain. Applications include the characterisation of standing waves and reflections in quasi-optical systems, the evaluation of very low return loss quasi-optical loads, and high range resolution radar.