GaAs monolithic integrated terahertz low-noise communication system transceiver front-end

A GaAs monolithic integrated terahertz low-noise communication system transceiver front-end, comprising an intermediate frequency circuit and a terahertz circuit arranged up and down, wherein the terahertz circuit comprises a local oscillator frequency tripler, a local oscillator co-directional 3 dB filter coupler, a radio frequency 180° filter coupler, and two terahertz GaAs monolithic integrated subharmonic mixers;

• the local oscillator co-directional 3 dB filter coupler and the radio frequency 180° filter coupler each comprise one ring-cylindrical resonant cavity and four rectangular waveguides, a height and a ring width of the ring-cylindrical resonant cavity are respectively equal to a long edge size and a short edge size of each of the rectangular waveguides, and an annular surface on both sides of the ring-cylindrical resonant cavity is provided with four corresponding sector-annular grooves, so that the ring-cylindrical resonant cavity is divided into four sector-annular resonant cavities comprising one big sector-annular resonant cavity and three small sector-annular resonant cavities, and a central angle of the big sector-annular resonant cavity is twice that of each small sector-annular resonant cavity;
• the four rectangular waveguides are correspondingly connected to the four sector-annular resonant cavities, respectively;
• the local oscillator co-directional 3 dB filter coupler takes a rectangular waveguide of the four rectangular waveguides that is connected to the big sector-annular resonant cavity as an isolation end, and the radio frequency 180° filter coupler takes the rectangular waveguide that is connected to the big sector-annular resonant cavity as an input end;
• radio frequency signals are filtered and coupled by the radio frequency 180° filter coupler into two signals, which respectively enter the corresponding terahertz GaAs monolithic integrated subharmonic mixers;
• a local oscillator signal is tripled by the local oscillator frequency tripler, and then inputted to the local oscillator co-directional 3 dB filter coupler, to be filtered and coupled into two local oscillator drive signals, which respectively enter the corresponding terahertz GaAs monolithic integrated subharmonic mixers to drive frequency mixing;
• and intermediate frequency components generated after the frequency mixing by the two terahertz GaAs monolithic integrated subharmonic mixer are separately inputted to the intermediate frequency circuit, 180° coupled and amplified, to output an intermediate frequency signal with local oscillator noise suppressed.