305-315GHz Sideband Suppression Mixer And Its Application

Terahertz?THz?waves lie in the frequency range between 100GHz¹0THz,is an electromagnetic wave between microwave and infrared light waves.Because of its spe-cial location,terahertz waves have both microwave and light characteristics.The terahertz wave has broad application prospects in the fields of communication,radar,atmospheric monitoring,biomedicine and so on.It has also attracted widespread attention from schol-ars at home and abroad.In terahertz wireless communication,it is necessary to ensure that the mixer in the transceiver is strictly homologous?use the same local oscillator source?in the double-band communication,so as to avoid the frequency offset causing the received signal to be missing or even garbled to be resolved Case.In actual communication,strict homology cannot be achieved,so double-sideband communication is not suitable for tera-hertz frequency bands,and single-sideband communication is the best way.As a key com-ponent of the terahertz transceiver system,the mixer has important research significance and application value for the sideband suppression mixer used to realize single-sideband communication.This article first introduces the research background of the subject and domestic and foreign developments,and analyzes the basic principle of subharmonic mixing based on anti-parallel diode pairs.According to the requirements of sideband suppression,a cavity filter that can be integrated in the mixer to suppress the upper sideband is developed.The filter is based on the TE₁₀₂/TE₃₀₁dual-mode resonant cavity.It has a controllable trans-mission zero and a good rectangular coefficient.It has a transmission zero at 316.4GHz,low insertion loss,and a symmetrical structure that is easy to process.Based on this,using the traditional branch design method,several passive unit circuit modules of the sideband suppression mixer are optimized first.Then,an anti-parallel Schottky diode pair model is established,and the overall circuit performance of the sideband suppression mixer is sim-ulated,and matching optimization research is performed.Waveguide filter matching and microstrip filter matching are used to match the RF transition part and the local low-pass filter part integrated with the sideband suppression filter to the two ends of the diode to achieve miniaturization of the microstrip circuit at both ends of the diode.Based on good simulation results,and through processing tests,it is obtained that the sideband suppres-sion mixer developed in this paper the conversion loss below 13dB is from 305GHz to315GHz at a local oscillator frequency of 158GHz and a local oscillator power of 2.5mW.The best conversion loss is less than 9dB,the out-of-band rejection is greater than 60dB,and the sideband rejection effect is good.This article innovatively realizes the upper sideband suppression by integrating the TE₁₀₂/TE₃₀₁dual-mode filter,and through the waveguide filter matching and microstrip filter matching diodes,the microstrip circuit at both ends of the diode is realized minia-turization.Finally,the development of 305³15GHz sideband suppression mixer was completed,and experimental research was carried out.Under the condition that the local oscillator frequency is 158GHz and the local oscillator power is 2.5mW,an out-of-band rejection of more than 60dB is achieved,and the in-band conversion loss is less than 13dB.Through the research in this paper,the feasibility of terahertz wave wireless communica-tion going to practical applications in the future has been verified,which has laid an im-portant theoretical and technical foundation for future terahertz wireless communication applications.