The Design Of Ferrite Film Phase Shifter

With the advent of the information age, wireless communication and data transmission play amore and more important role in modern life. With the coaction of constant stability and highfrequency electromagnetic field, ferrite permeability presents anisotropic. The phase shifter isgenerated when the electromagnetic wave through the ferrite and the values of phase shifter arecontrolled by the stable magnetic field. As the key element of controlling signal phase in the T/Rcomponents, ferrite phase shifter has been widely used in radar, navigation, communications,telemetry and remote test system. But the phase array radar has thousands of units which shouldbe used a phase shifter. Therefore, the performance and cost of phase shifter greatly influence theperformance and cost of radar.At the same time, the defects in large volume, high cost of ferrite phase shifter restricted thefurther development to miniaturization, downsize, high frequency, the integrated direction.Therefore there is an urgent need for the ferrite phase shifter to reduce the volume and improve itsresponse, and lower its cost technology. Then a ferrite film phase shifter which is based onmicrostrip line is designed in this dissertation.Based the above problems, a ferrite phase shifter which is based on the thin-film microstrip isdesigned through the relevant theoretical research of the suitable materials selection, the distributedparameter, transmission of design, simulation and optimization in this dissertation. The papermainly is discussed as followed: (1) According to the properties theory of ferrite magnetic spinmaterial, a microstrip of ferrite film phase shifter is designed based on transversely magnetic field.According to film integrated circuit technology, the design is using gyromagnetic materials of YIGand GGG, a layer of ferrite film is sputtered on the semiconductor substrate and then the microstripline turns and deposits on it. (2)The characteristic parameter of device is determined by analyzingthe characteristic of ferrite gyromagnetic material. The transmission equation of ferrite is obtainedthrough the study of the EM wave’s propagation characteristic in ferrite. The size of the ferrite usedin shifter is designed according to the ferrite characteristic parameter. (3)The basic workingprinciple of the ferrite thin-film phase shifter is discussed. The microstrip impendence matchingnetwork is set up and simulated by HFSS. To make the component working well, theλ4impedance match is adopted to deal with the impedance matching of device and broaden theoperating band, achieving the good impedance match. (4) The performance of the ferrite phaseshifter is analyzed with the impact of microstrip length and the distance S between microstrip on theferrite film phase shifter etc. The results show that as the microstrip length increased, the character of matching performance is better, the insertion loss increases; as the distance S between micriostripincreases, the differential bandwidth of model phase shifter also increases. These provide referencefor the future design of ferrite phase shifter.The results indicate that the designed ferrite phase shifter which works in X-band has better RFperformance with insertion loss less than 1dB, 346 degrees phase shift and over a 33 percentbandwidth.