Substrate Integrated Coaxial Line And Miniaturized Broadband Universal Radio Platform

The improvement of electronic technology promotes the development of various application systems.In an electronic system,the radio and microwave platform has a relatively high cost,a long development cycle,and at the same time has high requirements of technology and experience of the design and development researchers.Universal software definition radio platform(USRP)is an effective way to solve the above problems.In order to ensure the overall performance of the application systems,the USRP,which generally has a relatively high performance requirements in a comprehensive level.On the other hand,with the development of satellite application and UAV technology,there is an urgent need for the miniaturization of USRP.According to the requirement of the National Natural Science Foundation of instrument development project "synchronous multi-channel broadband channel measurement system for the new generation of mobile communication",the substrate integrated coaxial line and the miniaturized broadband universal ratio platform is studied.The main work of this dissertation is as follows.(1)The isolation of substrate integrated coaxial lines is tested for the first time,and a miniaturized surface mount substrate integrated coaxial filter is designed.The isolation of two adjacent substrate integrated coaxial lines as high as 100 d B,which not only requires the large dynamic range of measurement but also the detection of very weak signal easily to be interfered by other leakage signals.Thus,the measurement of isolation parameters is very difficult and it has always been a difficulty in the field of RF microwave measurement.In this dissertation,a method to suppress leakage and radiation interference is proposed,and an experimental device to measure the isolation parameters of the substrate integrated coaxial line and the grounded coplanar waveguide is designed.The isolation and transmission characteristics of the substrate integrated coaxial line are experimentally studied as well as the quantitative experimental results are given and are compared with that of the grounded coplanar waveguide,which verifies excellent isolation characteristics the of the substrate integrated coaxial line.This work not only provides the design criteria for the high-density routing of miniaturized broadband radio platform,but also provides the design basis for the application of substrate integrated coaxial line in other practical RF circuits,which fills a gap in the basic research work related to substrate integrated coaxial line.The substrate integrated coaxial band-pass filter designed in this dissertation shows good performance,straightforward installation,and can be mass produced.The filter can not only be used in the miniaturized broadband USRP,but also can be used in other RF systems.(2)A decoupling structure is proposed to improve the isolation of close spaced antennas.In the proposed decoupling structure,a step impedance resonator based on the slot line based on the asymmetric metallized via array is utilized.The resonator is placed on the ground plane between the transmit and receive antennas.When resonance occurs,the resonator is equivalent to the open circuit state at any position,so the current across the resonator on the ground is effectively suppressed.Compared with the common ground slot decoupling structure,the step impedance resonator decoupling structure based on the metallized vias slot line is not only good in decoupling performance,but also has a small dimension.It is suitable for the close space between the receiving and transmitting antennas and can be used in combination with the miniaturized broadband USRP.(3)A miniaturized broadband universal radio platform is developed.The miniaturized broadband USRP including receiver,transmitter,local oscillator and high-speed baseband.The operating frequency of radio platform receiver is from 100 k Hz to 9 GHz,which is realized by combining two heterodyne receiving channels and one direct sampling channel.The operating frequency of transmitter is from 1.5 MHz to 9 GHz.The USRP uses the substrate integrated coaxial line as the internal signal transmission line,and adopts several key technologies such as the single main module configuration,RF multilayer vertical stacking structure,miniaturized high selective filter and ultra-compact low spurious agile local oscillator,which solves the contradiction between miniaturization and performance.The overall architecture design of miniaturized broadband USRP as well as the technical specification simulation and verification,circuit,layout and structure design are implemented.The measured performance shows that its comprehensive performance including function,specifications and size is at the leading level in China.In this dissertation,the application of substrate integrated coaxial line is extended from the previous single component to a complete universal radio platform.The miniaturized broadband USRP has the advantages of small power consumption,small dimensions,comprehensive and advanced technical specifications,which is suitable for airborne and UAV platforms,and various applications such as test instruments,communication,target detection,positioning and navigation,spectrum monitoring,public security,and so forth.