X-band Broadband Microstrip Isolator Circulator Assembly Simulation Design And Implementation

With the development of active phased array,TR components are more and more widely used in various weapons and equipment recent years. The isolator-circulator components with same frequency duplex are essential units in TR components. As far as the development direction of its application in phased array radar is concerned,the size of the devices is required to be miniaturized,planar,thin filmed;the performance is required to be with wide frequency band,little insertion loss,high isolation,certain power handling ,and also with superior phase,amplitude consistency and magnetic shielding;meanwhile,the commercial requirements such as low cost,lot production should be met. Microstrip isolator-circulator components can meet all the requirements mentioned above furthest , and hence to research microstrip isolator-circulator components is meaningful. This thesis presents the research work such as designation and simulation of shielded-type microstrip isolator-circulator components in X band.Based on the design theory of wide frequency band and miniaturized circulator,this paper chooses YIG gyromagnetic material to design microstrip circulator covering the whole X band. The software HFSS(High-Frequency Structure Simulator)is used to simulate and optimize the circulator which performs well in circulating in the frequency range of 8~12GHz,and the circulator has a reverse loss large than 15dB and a forward loss less than 0.6dB. The structure parameters of the circulator are as follow:the diameter of outer circle is 4.4mm and inner 2.1mm,the added-impedance inductance is 0.2mm and matching inductance 0.45mm,the main factors which affect the circulator performance are analyzed by simulation. And the biggest problem (the power handling of thin-film load) which restricts the development of microstrip isolator is analyzed. The film layer structure of thin-film load and the manufacturer workmanship is discussed,both of them contribute to promote the load's ability of power handling. And the power handling of thin-film load advances from 2W to 5W by designation manufacturer and experiment.Secondly,this paper investigates the magnetic shielding technology applied in the microstrip product,and develops semi-enclosed,with excellent effect of magnetic shielding microstrip product which has order of magnitude promotion in the criterion of magnetic leaking comparied with the traditional open type.And finally , through the thin-film microstrip circuit workmanship including manufacturer,welding,assembly and so onthis paper develops the sample of shielding-type microstrip isolator-circulator assembly in X band,which dimensions are:9mm×10.4mm×4mm(max),the distance between microstrip line and ground is 0.6mm.