Polarisation insensitive in-situ resistive sensor for high-power microwave pulse measurement in TE11 mode circular waveguide

A resistive sensor (RS) based on the electron heating effect in semiconductors is considered for high-power microwave pulse measurements in TE₁₁ (H₁₁) mode circular waveguide. A plate-shaped semiconductor sample with contacts on its top and bottom is used as the sensing element (SE). A three-dimensional finite-difference time-domain method was applied for the calculation of the electric field strength in the SE. The optimal dimensions and specific resistance of the SE have been found, providing a flat frequency response for the RS when the SE position in the waveguide coincides with a polarisation plane of the wave. A polarisation-insensitive layout of the RS consisting of two SEs placed at 90° from each other has been proposed. It is shown that the sum of their signals (within °7°) is independent of the position of the polarisation plane in the waveguide.