Design And Research Of Terahertz Broadband Waveguide Coupling Circuit

Terahertz(THz)wave is the electromagnetic wave in the frequency range of 0.1-10 THz,which is between microwave and infrared.Terahertz wave is widely used in radio astronomy,medicine,electronics,physics and biology because of its high spectral resolution,high security,fluoroscopy,transient and broadband.Terahertz technology mainly includes terahertz radiation,terahertz transmission and terahertz detection.Terahertz high sensitivity detection technology is mainly used in the field of radio astronomy.The radio astronomical telescope receiver uses a highly sensitive detector to obtain the radio frequency signal.The radio frequency signal is mixed with the local oscillator to produce the intermediate frequency signal,and the intermediate frequency signal is magnified and analyzed by the spectrometer.The RF and local vibration signals enter the superconducting electronic mixer through the RF coupling circuit,and the coupling efficiency of the RF coupling circuit is an important parameter to measure the performance of the telescope receiver.In this paper,the HFSS simulation software is used to design a ultra wideband waveguide RF coupling circuit.The frequency range of the coupling circuit is 0.8-1.5THz,and the proportional model is made to test.The main contents of this paper include:1.The design of RF coupled circuit based on HFSS simulation.The components of the coupling circuit are: rectangular waveguide,waveguide to microstrip conversion,and microstrip filter.The HFSS simulation software is used to optimize the coupling circuit.The main optimization parts are the size of the waveguide,the thickness of the dielectric plate,the structure of the waveguide to the microstrip,the height of the metal resonator.The impedance of the circuit feed port is calculated.The design requirement of the circuit is that the impedance of the feed port is close to 50?.2.The scale model is made and tested.The circuit is amplified according to the ratio of 1:233,and the working frequency of the circuit is reduced to 3.43-6.44 GHz proportionally.A proportional model is made to measure the S parameters of the waveguide coaxial converter,as well as the reflection coefficient of the input end of the proportional model,and the impedance of the feed port of the proportional model is calculated by the formula.3.The measurement results are compared with the simulation results.Comparing the impedance of the feed port of the proportional model and the impedance calculated by simulation,the results of the two are basically the same,and there is a certain deviation.After deviation analysis,the resistance deviation between the measured results and the simulation results is 0.46%,the reactance deviation is 0.28%,which is in line with the design requirements of the paper.