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Light- and voltage-induced changes in the microwave reflectivity of semiconductors can be used to study the kinetics and mechanisms of electron transfer at semiconductor|electrolyte interfaces. The theory of the method is developed and illustrated by numerical calculations of the steady-state microwave response for low-doped silicon. The results define the range of rate constants that should be experimentally accessible using microwave reflectivity methods. The time and frequency responses of light-induced microwave reflectivity changes are considered, and it is shown that they can be used to derive values of electron transfer and recombination rate constants.

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Phase noise is one of the fundamental performance parameters in modern radar, communication, spectroscopic, and metrological systems. In this paper a phase noise theory has been developed for FMCW radar systems. A new design equation has been derived to specify the maximum bound on the allowable source phase noise level in radar systems. The non-linear phase noise decorrelation function due to coherent mixing has been analysed for propagation delays less than the coherence time of the reference oscillator, and the spectral broadening of target responses has been discussed for delay times greater than the coherence time. The effects of the subsystems in the transceiver chain are presented and a new model of phase noise in ADCs is discussed. Phase noise modelling techniques are presented, followed by a comparison of a PLL frequency synthesiser with a low-noise frequency synthesiser to demonstrate the reduction of phase noise sidebands for improved detection and tracking performance. Practical measurements from two millimetre wave FMCW radar systems utilising the two frequency synthesisers have been presented to validate the developed theory.