Interaction of a semiconductor sample partly filling a waveguide´s window with millimetre wave radiation

Interaction of a semiconductor sample with an electromagnetic wave within the millimetre range has been investigated. A three-dimensional finite-difference time-domain method was applied to simulate wave propagation within a waveguide segment with the semiconductor sample attached to a wide wall of the waveguide. The electric field distribution, voltage standing-wave ratio and the average electric field dependencies in the 78-118 GHz frequency range have been determined for several sets of dimensions and specific resistances of the sample. These investigations have been the basis for the design of the resistive sensor (RS) based on the electron heating effect and devoted to high-power millimetre-wave pulse measurement. By choosing the dimensions and specific resistance of the sample, the decrease in the electron heating effect with frequency as well as the decrease of electric field in the waveguide due to wave dispersion were compensated by an increase in the average electric field. Therefore an RS having practically unchanging sensitivity in a waveguide´s frequency range has been proposed.