Antenna effects in detection of 100 GHZ radiation by high electron mobility field-effect transistors

Detection of 100 GHz electromagnetic radiation by a GaAs/AlGaAs high electron mobility field-effect transistor was investigated at 300 K. The radiation was linearly polarized and measurements were carried out as a function of the angle r between the direction of polarization and the symmetry axis of the transistor. Source-drain photovoltage measured showed the angular dependence A₀ cos²(alpha - alpha₀) + C with A0; alpha₀ and C dependent on the electrical polarization of the transistor gate. A response of the transistor chip (including bonding wires and the substrate) to 100 GHz radiation was numerically simulated. Results of calculations confirmed experimentally observed dependencies and allowed to give the interpretation to the origin of the measured signal as resulting from excitation of two effective oscillators.