Waveguide cold noise source and temperature control method

The invention discloses a waveguide cold noise source and a temperature control method. The problems that in the prior art, the output temperature of a waveguide cold noise source is unstable, liquid nitrogen is prone to leakage, and a matched load is not easy to replace are solved. The waveguide cold noise source comprises a sealed liquid nitrogen container, a heat transfer structure, a waveguide mounting frame, a waveguide, a load and a temperature control structure. The waveguide mounting rack is fixedly connected with the liquid nitrogen container through a heat transfer structure. The waveguide is a hollow pipeline which is installed on the waveguide installation frame and penetrates through the groove path. The load is located in the waveguide cavity. The temperature control structure comprises a heating film located between the liquid nitrogen container and the waveguide installation frame, a temperature sensor and a PID controller. The temperature sensors are installed in the waveguide in a distribute