The history of the development of the magic-T in MIC and MMIC is presented briefly

and the difficulty and disadvantage in analysis and design of such magic-T is pointed out.The principle of a model of a magic-T formed by microstriplines and slotlines is explained and detailed equivalent circuits as well as equations based on it are given.To design magic-T effectively

a new method which combine the method of equivalent circuit and FDTD to design magic-T is given.Then an example of designing a magic-T is showed and all process of designing the magic-T in such method is presented in details.This magic-T is similar to one reported by Mzsayishi Aikawa

but is made in MIC and its center frequency is 6GHz.It shows good performance between 3.3GHz to 9.9GHz.The reason for using full-wave analysis is presented.The perfectly matched layer (PML) and non-uniform meshing techniques are used for getting accurate results in analysis by FDTD method.