Design Of Ku-band Bipolar Microstrip Circulatory Isolation Component

Ferrite circulator was a kind of nonreversible microwave device with several ports.Because of its forward transmission and reverse isolation,it is often used in the transceiver system of phased array radar,mobile communication base station,etc.It is apply used in spaceflight,microwave communication,aviation and other realms.Bipolar microstrip circulator isolation component is to add a circulatory junction on the basis of ferrite circulator and convert it into bipolar microstrip circulator isolation component.In order to get a larger isolation between two circulatory junctions,one port will be matched with a built-in load,so the 4-port device will be changed into a 3-port device.In the transceiver module,generally,three ports are connected to the transmitter separately Terminal,receiving terminal and antenna solve the problem of integrated transceiver,stage isolation and sharing one antenna.With the rapid development of microwave integrated circuits,the research on miniaturization and ultra bandwidth of devices is of great significance.With the actual needs,this paper selects the Ku-band operating band in the 14 GHz ? 18 GHz bipolar microstrip circulator isolation component as the research object.Firstly,the related theory of the key material of the device,the gyromagnetic ferrite,is analyzed and discussed,which provides an important theoretical analysis for the later design and analysis,and the selection of materials.Then,the working principle of the bipolar microstrip circulator isolation component is analyzed.The size,technical specifications and structure of the module are proposed.The network and field are analyzed.Based on the study of single-stage circulator,the characteristics of double Y-junction circuit are discussed.A new circulator is added,which is matched by quarter wavelength impedance conversion.High frequency structure simulator software and Auto CAD software are used for joint simulation and optimization,so that the index parameters are optimized and the size is minimized.Using the technology of thick film printing in the form of microstrip,the device is made in kind.Through the test of the real object,the fine-tuning circuit makes the index reach the best.The test results show that the performance of Ku-band bipolar microstrip circulator isolation component is excellent,the geometric dimension is 7 mm × 8 mm × 3 mm(max),the relative bandwidth can reach 25%,the VSWR of the port voltage is less than 1.25,the insertion loss is less than 0.60 d B,the two isolation degrees are greater than 20 d B and 32 DB respectively,and the test and simulation results are basically the same,and each index meets the system requirements.