Research Of Up/Down Converter Module For Millimeter-wave Ultra Wideband Direct Acquisition System

Millimeter wave has always been a research hotspot in radar,remote sensing,imaging and security,in order to meet requirements on high data rate,large communication capacity,and some potential applications,research on high-frequency devices has been rapidly growing in the past decades.There has increased a requirement on the development of the millimeter-wave circuits for use in satellite receiver systems,future personal communication systems,and millimeter wave radars.As a key component of millimeter wave radar,converter module affects the performance of the whole system and plays an important role.This paper focuses on the design index,according to the requirements of on-board radar project in the teaching and research office,and designs an up/down converter module for millimeter wave ultra wideband direct acquisition system.Firstly,combined with the research background and practical application significance of converter modules,the research status and future development trends of converter modules at home and abroad are summarized.Secondly,the basic principles and technical specifications of the key components in the converter module are fully analyzed,which provides an important theoretical basis for the selection of subsequent link chips.In this paper,the technical solutions of common converter modules are deeply studied,and the advantages and disadvantages of each scheme are summarized and compared,which provides an important idea for the development of ultra wideband frequency converter modules scheme.Then combined with the design index,the ultra wideband frequency converter module is designed synthetically,which is divided into three parts: up converter module,down converter module and power combiner module.The up converter module converts the IF signal from 2.25?3.75 GHz to the RF signal from 27?33GHz through the scheme of "mixing frequency + quadruple frequency".The down converter module uses the secondary conversion scheme of superheterodyne receiver to convert the RF signal from27?33GHz to the baseband signal with the center frequency of 140 MHz and the bandwidth of 30 MHz.The power combiner module is designed hierarchically,and then spliced and adjusted.Finally,the cavity design and assembly drawing of up converter module,down converter module and power combiner module in the ultra wideband frequency converter module are carried out respectively,and each module is processed and manufactured.After testing and debugging,the test results show that: The mixing frequency spectrum of up and down converter module is relatively pure,and the spurious signal can be suppressed or filtered,and the suppression ratio is more than 40 dBc.The measured return loss of the power combiner module is less than-20 dB,the transmission coefficient is about-6dB,and the isolation of adjacent ports can reach below-20 dB or less,the test results are in good agreement with the simulation results.The synthesis efficiency of the real object in the passband is more than 93%,and the maximum synthesis efficiency is more than 97%.