Mechanism of Radiation Coupling to Plasma Wave Field Effect Transistor Sub-THz Detectors

Detection of 100 GHz and 285 GHz electromagnetic radiation by GaAs/AlGaAs field effect transistors with the gate length of 150 nm was investigated at 300 K as a function of the angle α between the direction of linear polarization of the radiation and the symmetry axis of the field effect transistors.The angular dependence of the detected signal was found to be A cos 2 (α-α0)+C.A response of the transistor chip (including bonding wires and the substrate) to the radiation was numerically simulated.Calculations confirmed experimentally observed dependences and allowed to investigate the role of bonding wires and contact pads in coupling of the radiation to the transistor channel.