Development Of Key Components Of Spread Spectrum Module Of Terahertz Vector Network Analyzer

Since the fifth-generation mobile communication technology was promoted to civil-ian use,millimeter-wave technology has been brilliant in commercial applications.How-ever,people are not satisfied with the achievements of existing communication technol-ogy,but continue to explore the direction of the sixth-generation mobile communication technology with larger capacity and more stability.Terahertz communication technology is a hot research topic in the sixth generation mobile communication technology.To study terahertz technology,test equipment in this frequency band is required.Vector network analysis is one of the most widely used test equipment.Because the test frequency band of the vector network analyzer is developed from the low frequency,and the detector and filters of the low frequency band have better per-formance.Therefore,in order to test the signal characteristics of the terahertz frequency band,it is necessary to down-convert the signal to the low frequency band.The industry often uses an external frequency expansion module to expand the spectrum of the vector network analysis.In this paper,a 200 GHz harmonic mixer and a W-band frequency multiplier as a local oscillator frequency source are designed for terahertz vector network analysis.Both devices use a parallel diode pair as the core element.When the local oscillator frequency is 97.5 GHz,the best frequency conversion loss is obtained in the frequency band of 190-210 GHz.The optimal conversion loss at this LO frequency is 6 d B,and the loss in the 190-210 GHz band is less than 15 d B.The triples of the frequency multiplier result in a relatively flat power output in the 87-97 GHz band.At an excitation power of 10 d Bm,a maximum output power of -21 d Bm is achieved around 88 GHz.It was also found that the output of its fivefold frequency obtains relatively flat power in the 75-85 GHz frequency band.At an excitation power of 10 d Bm,a maximum output power of -20 d Bm is achieved around 81 GHz.The two output curves can complement each other at low frequency and high frequency,so this characteristic can be used to obtain a W-band frequency multiplier with larger output power.In the design of the step-impedance low-pass filter of the frequency multiplier,the out-of-band rejection characteristic of the filter is improved by increasing the distance between the high-impedance line and the ground.This paper completes the simulation of terahertz mixer and W-band frequency mul-tiplier,and analyzes the simulation results to derive all circuit structures of the designed devices.Next,the processing and assembly of the designed circuits and the test environ-ment are completed,and the experimental tests and analysis of the multiplier and mixer are carried out.Finally,the physical implementation of the frequency multiplier and mixer is completed,which achieves the expected purpose.The diode pairs used in the frequency multiplier of the terahertz mixer designed in this paper are all from domestic manufactur-ers,and the design of this subject is completed with a lower cost.