0.3THz Monolithic Integrated Frequency Multiplier

Terahertz technology has important application value in the fields of meteorological monitoring,medical imaging,security imaging,wireless communication and other fields.The reason why the terahertz band has not been used and developed for a long time is because of the lack of electronic devices that can be used in this band,especially the lack of a signal source that can provide the necessary signal power and frequency agility.Among them,the all-solid-state terahertz frequency doubling source has attracted much attention due to its compact structure,small size,and low DC input power.The all-solidstate terahertz source multiplies the input microwave and millimeter-wave low-frequency signal by non-linear frequency doubling to output the required terahertz frequency band signal.660GHz is one of the atmospheric windows,which can be used to detect the atmospheric humidity profile to assist meteorological detection.In this paper,a 330 GHz tripler is developed as the local oscillator to drive the 660 GHz subharmonic mixer.At present,the research of terahertz frequency multiplier in China mainly adopts the type of hybrid integrated circuit,which is difficult to achieve higher frequencies,and the actual test level is also difficult to approach the simulation level.Therefore,the research of the 330 GHz tripler in the form of a monolithic integrated circuit is carried out as follows: analyzes the formation and characteristics of planar Schottky diode rectifying contact and ohmic contact,and gives the I-V,C-V relationship of the diode.Qualitative and quantitative analysis of the surface channel planar Schottky barrier diode die model and three-dimensional electromagnetic model,and various factors affecting the characteristics of the diode.Based on the process requirements of domestic processing institutions,the design criteria and simulation optimization methods of the diode are given to obtain the required 330 GHz monolithic integrated planar Schottky barrier diode.Based on the designed diodes,the simulation method of the frequency multiplier circuit is studied,and a more efficient simulation design method is given.Finally,a 330 GHz monolithic integrated tripler is used to drive the 660 GHz sub-harmonic mixer.The monolithic circuit uses 12 um thick GaAs as the substrate material and the diode substrate.The circuit topology adopts the structure of the diodes connected in parallel in the same direction.When the input power is 20 mW,the maximum output power is 0.451 mW,and the corresponding triple frequency efficiency is 2.26%.The research results in this article can accumulate valuable research experience for the development of corresponding and higher frequency monolithic integrated triplers in China.