Shift Lithium Ferrite Microwave Phase In Applied Research

Phase shifters are widely used in radar and communication system, microwave instruments and measurement system, especially in phased-array radar system. Microwave ferrite phase shifters have dominated for many years above S-band in passive matrix due to high power capacity, low insertion loss, high reliability and long service life. The performance of ferrite phase shifter is influenced by ferrite material properties and structural design.Li ferrite has high ratio of Br /Bm, wide adjustable range of Ms, so has importance application in X~Ku-band microwave ferrite phase shifter. LiTiZn ferrites for X-band ferrite phase shifter were prepared by Ti substitution and Zn substitution, respectively. The influences of Ti substitution and Zn substitution on material properties were studied. The main composition of Li0.52Zn0.16Ti0.2Fe2.12O4 is confirmed and the samples have the following properties : 4πMs =2637Gauss,Br=228mT,Hc=117A/m,Br/Bm=0.86,Tc=463℃,ρ=3.12×107?·m,ε′(1.8GHz)= 14.6.The structure design of phase shifter was simulated by Ansoft HFSS 10. The simulate results of waveguide-ferrite phase shifter are:︱S21︱<0.5dB,VSWR<2,difference phase shift is 346°. The magnetization process of ferrite phase shifter was analyzed, on this basis, a driver circuit for latching ferrite phase shifter was designed to measure phase shifter.The relate parameter of a waveguide– ferrite phase shifter was measured, and the results show that :︱S21︱>2dB,the difference phase shift is 353°. The difference between simulation and measure were analyzed in detail.