Design And Simulation Of Ka-band Double-film Structure Microstrip Circulator

The circulator is an important component of the microwave communication system,which is mainly used for receiving and transmitting communication signals.With the rapid development of mobile communication,the miniaturization,planarization and integration of circulators have become an important research direction.The advancement of film manufacturing technology has promoted the development of film circulators.The circulator made by films with excellent performance has lots of advantages compare to normal circulators,including small size,light weight and easy integration.The research on the circulator made by films is of great significance for reducing weight and size of circulators.This paper is about to study how to prepare film microstrip circulator by Ba M film with excellent performance.In this paper,a Ba M film circulator that of center frequency is 37.5 GHz is designed by using the traditional circulator structure,the circulator is optimized and has good performance.According to the traditional film circulator structure,a new kind of circulator structure is proposed to solve the problem that single layer film of traditional circulator is hard to prepare.A circulator that made by double layers film with a center frequency of 37.5 GHz is designed.Compared with the traditional structure circulator,the new structure circulator exhibits superior performance such as bandwidth.Then,the circulator with double-layer film structure is studied in depth,and it was concluded that the performance of circulator was the best when the thickness of the two films was equal.Finally,the real circulator is prepared and tested.The test data show that there are some errors in the center frequency of the circulator,and the parameter curves of the return loss and isolation show the same trend as the simulation results,but the insertion loss parameter has a large deviation,the main reason is that the magnetic field strength of the applied to the circulator cannot be determined,and there is an error between the ferrite film and the ideal simulation model.The two-layers film structure circulator proposed in this paper can improve the performance of circulator such as the bandwidth of the circulator by making full use of the film preparation technology.Compared with the traditional structural circulator,although the two-layers film structure circulator is more complicated to make,especially in preparation process of the ferrite film and microstrip,the performance of the new structure circulator is more excellent,which provides a reference for research on the circulator in the future.