Microwave Intermediate Frequency Equivalent Circuit of GaAs High Electron Mobility Field Effect Transistor Terahertz Detectors

Field effect transistor (FET) based terahertz rectifiers are promising candidates for sensitive, room-temperature operated high speed (THz) detectors, e.g. in communication, medical, biochemical, security, quality control applications, or beam diagnostic applications at particle accelerators. This paper investigates the equivalent circuit in the intermediate frequency band from 0.1 to 65 GHz with S-parameter measurements in order to enable implementation with high speed post detection electronics. Preliminary results are obtained by de-embedding On-Wafer measurements and compared with theoretical expectations from hall measurements and a simplified equivalent circuit. The knowledge of the channel behavior and impedance is mandatory for impedance matching to IF circuitry in advanced detector designs.