Fabrication of a Novel GaAs Thermopile Sensor for RF Amplitude Demodulation

In this letter, a novel fabrication of straight-channel RF AM demodulator based on thermopile is presented. Its structure consists mainly of CPW line fed with AM signal, resistors and thermopiles to detect the demodulated signal. The structure is fabricated using GaAs Microwave Monolithic Integrated Circuit (MMIC) technology. Experiments are implemented and the results show that this thermopile-based demodulator is able to perform demodulation of AM signal with carrier frequency of 0.01-10 GHz and signal frequency of under 5 kHz. The influence of thermopile length on the performance is also studied and the result shows that when the thermopile length gets larger, the output amplitude of the demodulated signal gets larger, but its bandwidth gets smaller. In our scenario, the length of the thermopile can be set as
$50~\mu \text{m}$
as a tradeoff between amplitude and bandwidth. [2022-0187]