Integrated Thermal Analysis Of Microwave Circuits In Time Domain Electromagnetic Spectral Element Method

Nowadays, numerical methods are becoming more and more popular to solve a series of problems with huge amounts of calculation and complex structures instead of analytical methods. The spectral-element time-domain method (SETD), which is used in this dissertation, is a special form of the finite-element time-domain method. The advantage of this method is that it not only has the explicit characteristic as the FDTD, but also has the flexibility to handle some very complex structures. Gauss-Lobatto-Legendre polynomial is employed as the interpolation basis function. Calculation errors can be reduced significantly by increasing the order of the basis functions.Thermal effects caused by surface resistance of metal are more and more serious as the working frequency of the microwave circuit is getting higher and higher. Moreover, the development of miniaturized circuits also affects the reliability of the circuits. The thermal effects of microwave circuit caused by metal loss is discussed in this dissertation, by solving Maxwell’s equations and the Heat conduction equations, based on spectral-element time-domain method.Firstly, the electric field vector wave equation and the basic equations of heat transfer are introduced in this dissertation, which are then discretized by spectral-element time-domain method, to establish the differential equations. Some specific examples demonstrate the accuracy and efficiency of the proposed method. Secondly, the basic solving model of electric-thermal coupling is introduced, followed by specific method for solving microwave circuit conductor losses. Some microwave circuits are simulated according to this method. Finally, a parallel accelerate method is developed for microwave passive circuits EM-thermal integrated analysis, in order to handle large-scale problems.