Design Of 220GHz Sub-harmonic Mixer Based On Planar Schottky Diode

With the development of the satellite payload technology,the spectrum resource in C band and Ku band is becoming increasingly limited.In order to achieve larger capacity,higher speed satellite communication and higher resolution,more abundance remote sensing detection,the working frequency band of satellite is becoming higher and higher.The payload,working at millimeter wave(30GHz~300GHz),Terahertz(THz)wave(0.1THz~10THz)band,becomes an important research direction.Terahertz mixer,the key component of the solid-state terahertz transceiver front-end,which is widely used in terahertz communication and remote sensing system,is a key research direction of terahertz technology.The harmonic mixer requires low frequency of local oscillator,just half of the fundamental frequency mixer,which can be a good solution to the problem that high power local oscillator in terahertz band is difficult to obtain.It is the main research content of this thesis.This thesis introduces the development of the THz mixer based on Schottky diode at home and abroad first,and then describes the working mechanism of planar Schottky diodes and sub-harmonic mixer based on Schottky barrier diode and its advantages.What's more,the thesis discusses a precise diode modeling method for220 GHz sub-harmonic mixer,which divides the diode model into two parts: one is passive linear parasitic parameter model,the other is active nonlinear model.Then,extracts S-parameters to characterize the high frequency parasitic parameters.This thesis combines extracted S-parameters and diode SPICE model to build the full diode model.On this basis,the topology of 220 GHz mixer,passive circuit design and optimization of the mixer overall performance are systematically studied respectively.A waveguide to Suspended Substrate Microstrip Line Transition and a Wide Stopband Lowpass Filter Based on Beeline CMRC were designed in this thesis.The quantitative machining and assembly error analysis are done,finding out that the size of DC grounding circuit is a sensitive point.The mixers were tested by both Y factor hot-cold load method and typical conversion loss measurement method.The resultshows that the average effective noise temperature of the mixer between212~228GHz is less than 900 K.The conversion loss is under 13 dB in the range of201~240GHz,and the average conversion loss is under 9dB.The minimum conversion loss is 6.3dB at 227 GHz.The test results match well with the simulation results,and show that this design reach the state of the art in domestic and aboard.The results of this thesis will provide reference for researches of terahertz subharmonic mixer with more excellent feature and higher working frequency.