SAN JOSE STATE UNIVERSITY College of （圣荷西州立大学学院）.pdfVIP

SAN JOSE STATE UNIVERSITY College of Engineering Department of Electrical Engineering Final Project EE172 course Report Stripline Circulator Submitted by: Nguyen, Tong Professor: Dr Ray Kwork May 28, 2011 ABSTRACT The operation of symmetrical circulator is described in term of the counter rotating normal mode of the ferrite. The rotating modes are applied by magnetic field form a stationary pattern which can be rotated in space to isolate one of the ports of the circulator. A field theory of the strip-line Y- junction circulator operating with n=1 will be presented in this report. This report includes equation designs, material of ferrite, dimensions and result of simulation by High Frequency Simulation Structure (HFSS). INTRODUCTION The three port circulator is a unique nonreciprocal symmetrical junction having one typical input port, one output port, and one decoupled port. The purpose of junction circulator is energy conservation. It means that the only matched three port junction corresponds to the definition of the circulator. A wave incident in such a junction at port 1 is emergent at port 2, one incident at port 2 is emergent at port 3, and so on is a cyclic manner. The purpose of introduction in this report is to provide the phenomenological description of the operation of this device. The geometry of the stripline circulator geometry is showed in Fig 1. It consists of two ferrite planar disk resonators separated by a disk center conductor symmetrically coupled by three transmission lines. Fig 1: Schematic diagram of three-port stripline circulator The gyro-magnetic material is magnetized perpendicularly to the plane of the device by a static magnetic field. A circulator conditio