Research And Design Of Microwave Circulator/isolator Based On Ferrite

The microwave ferrite circulator is a common microwave device with plenty of applications,such as in radar systems,as a transmit/receive component for interstage spacing.Due to its non-reciprocal nature,it have the function of transmitting signals.At the same time,it can also be used as a switch for transmitting and receiving a common antenna for switching the transmission and reception status of signals.You can also connect one port of the circulator to the load and use it as a isolator.According to the structure,the circulator is mainly divided into waveguide type,microstrip type and strip type.The waveguide type is mainly used in the low frequency field,and the volume is large.The microstrip type circulator is mainly used in an environment with a relatively small bandwidth.Strip-line circulator according to its characteristics,small size,wider bandwith,and the manufacturing process is relatively simple.With the advancement of the telecommunication,the engineering requirements are increasingly diversified,which poses new challenges for the development of various types of microwave devices.Therefore,for the new microwave frequency band,the design and development of circulators for engineering requirements is particularly important.Based on the theoretical analysis of ferrite and strip circulators,according to the design method and process of circulator,and proposes the corresponding line circulator design scheme for 3.3-3.6GHz and 1.9-2.6GHz respectively,and the 1.9-2.6GHz line circulator processed the sample,taked the test.Based on the work of this article,it is divided into five parts to introduce the design work of the line circulator: The first part introduces the background of the design,the application of the circulator in the microwave system is briefly explained,and then introduced the development of the circulator in engineering and academia.Then analyzes the circulator from the theoretical point of view,mainly from two aspects,one is the microwave ferrite material,the other is the parameters of the circulator and the circuit design,summarized the problems and parameters that need to be paid attention to in the design of the circulator.And then mainly proposes a circulator design scheme for the frequency range of 3.6-3.6GHz in the 5G frequency band.In this scheme,the return loss and isolation generally lower than-18 dB in the entire frequency band,the insertion loss is higher than-0.5dB in the entire band.VSWR is less than 1.35,less than 10 mm in diameter,adapt to conventional standards.And then mainly designs the 1.9-2.6GHz strip circulator.The model of the circulator is obtained through simulation and optimization,and the physical sample of circulator and isolator are processed.The return loss and isolation of the circulator are below-20 dB.The insertion loss is above-0.5dB,and VSWR is less than 1.25,achieving good matching performance.The last is summary and outlook,summarizes the main work and design deficiencies of this paper,and puts forward the direction for the next step.The significance of this work is mainly to verify the practical value of the circulator through the engineering environment and technical indicators.The academic value of this paper is offered the ideas and solutions via the design of the circulator through the simulation optimization and processing of the double Y junction circulator.