Fig. 1. (a) Schematic diagram of AlGaN/GaN HEMT terahertz detector; (b) Actual picture of AlGaN/GaN HEMT terahertz detector; (c) Equivalent circuit of AlGaN/GaN HEMT terahertz detector; (d) Homodyne-detection responsivity of the detector in the band of 334-343 GHz; (e) Homodyne-detection responsivity as a function of the received power

Fig. 2. Block diagram of homodyne transmitter-transceiver chain based on AlGaN/GaN HEMT terahertz detector

Fig. 3. SNR of the homodyne receiver as a function of the received power with different receiver bandwidths

Fig. 4. (a) Transmitted and received waveforms without nonlinear compensation; (b) Transmitted and received waveforms with nonlinear compensation

Fig. 5. Block diagram of heterodyne transceiver system based on AlGaN/GaN HEMT terahertz detector

Fig. 6. SNR of the heterodyne receiver as a function of the received power with different signal bandwidths

Fig. 7. Waveforms of the base-band signal and the IF signal with a local terahertz power of 0 dBm and a signal bandwidth of 10 MHz

Fig. 8. SNR as a function of the receiver bandwidth for the two different receivers with the same received power of −11 dBm

Table 1. Extrapolated received power with SNR=0 dB and the NEP for homodyne receiver with different receiver bandwidths

Table 2. Extrapolated received power with SNR=0 dB and the NEP for heterodyne receiver with different receiver bandwidths