Research On 4THz Harmonic Mixer

The unique advantages of terahertz waves make it widely used in many disciplines,and terahertz basic technology and related devices have become a central issue.The theoretical system and device applications of terahertz technology below the 1THz frequency band are becoming more and more mature,and limited by various factors such as the actual manufacturing process and theory,higher frequency terahertz devices still need to be studied.In order to meet the frequency conversion requirements of the 4THz frequency band and build a terahertz spectrometer with higher detection accuracy,it is urgent to study the4 THz frequency band mixer.In order to meet the mixing requirements in the 4THz frequency band,this paper first studies and implements a high cut-off frequency Schottky diode.Using the Schottky diode design optimization method proposed in this paper,a three-dimensional packaging model and a single-die physical model of the diode were successively established,and the peripheral parasitic parameters and junction parameters of the Schottky diode were simulated by using HFSS and TCAD software.Finally,a complete terahertz Schottky diode model is established.Then design and optimize the passive circuit module of 4THz harmonic mixer.When the passive circuit performance of each module reaches the design index,the Schottky diode model and each passive circuit module are spliced together to optimize the complete circuit performance of the mixer.In the end,the two 4THz eighth harmonic mixers have achieved the goal of RF reflection loss better than 10 d B and frequency conversion loss lower than 65 d B in the ultra-wideband RF range of 3.4THz-4.4THz.In the ultra-broadband radio frequency range of3.4THz-4.4THz,the 4THz fourth harmonic mixer has RF return loss better than 10 d B and frequency conversion loss lower than 86.7d B.The designed 4THz eighth harmonic mixer is intended to be used in a free electron laser-based terahertz spectrometer,and its function is realized in the spectrum transformation module.