Research On 1THz Monolithic Sub-harmonic Mixer

Benefit by the uniqueness of terahertz waves,it has huge potential in many fields and cross-disciplines,and has important research significance.Terahertz science and technology is one of the hottest cutting-edge technologies nowadays.With the rapid development of electronics and communication science,the research on various devices and systems working in the lower terahertz frequency bands has become increasingly abundant.Because of the incompleteness of the theory,technology and technology,there are still many problems unable to solve in the higher terahertz frequency.In recent years,domestic and foreign countries have gradually focused on the higher frequency bands of terahertz,but many studies are still in the trial stage.No matter what frequency band circuit device or system is working,it may involve spectrum conversion and shift.Such a function is realized through the design of the mixer.Mixing technology is relatively advanced in the low frequency band,in order to satisfied the frequency conversion requirements in the higher terahertz frequency band,it is of great research significance to research mixers that can work stably in 1THz frequency bands.In this paper,based on the basic mixing principle,the 1THz monolithic integrated harmonic mixer is researched.Simulate and develope the mixer Based on the domestic processing level at present,and the fourth harmonic mixer and eighth harmonic mixer that satisfied the requirements are designed.Combined with advanced semiconductor circuit technology,the overall circuit is based on extremely thin gallium arsenide substrate manufactured,which works in a single-chip integrated manner.Terahertz mixer uses harmonic mixing,for the fourth harmonic mixer and the eighth harmonic mixer,the LO frequency is only one-fourth and one-eighth or less of the RF frequency,which effectively reduces the demand for the LO source.Through the joint simulation research of different electromagnetic softwares,a new Schottky diode model is constructed and analyzed.Design and optimize the various sub-circuits of the mixer to meet the corresponding indicators,and then combine them into an overall circuit.After repeated adjustments and optimizations,the mixer has an ultra-wide band RF range of 750GHz~1100GHz to ensure stable IF output,and achieve the goal of frequency conversion loss is always less than 30 dB,the optimal conversion loss is 22 dB.After the simulation is completed,processing and assembly are performed and an experimental platform is set up to test the performance of the fourth harmonic mixer.The measurement of conversion loss in the RF frequency range of 800GHz~1050GHz is less than 42 dB,and the optimal conversion loss is 24.6dB.The designed mixer is intended to be used in the special package of terahertz instruments,to realize the corresponding function in the spectrum expansion module.The research in this article is a tentative preliminary exploration of the 1THz frequency mixer,limit by computer simulation conditions,processing technology conditions and experimental conditions,there are many problems needs to be solved and improved.Follow-up of this reseach is ongoing.