Analysis Of Time Domain Integral Method For Microwave Circuit And Antenna Problem

Numerical computational methods of electromagnetic field change quickly. Different methods in computational electromagnetic field can solve all kinds of realistic complex electromagnetic field problems, which are very effective tools and measures. For solving microwave antenna and circuit problems, this paper is based on time domain integral equation method, with marching-on-in-time method as numerical solution. Besides, modified nodal analysis method in circuit analysis is also combined here. This paper focuses on lumped elements loaded microwave antenna, circuit issues and electromagnetic field-circuit coupled problems. Combined with modified nodal analysis method, time domain integral equation method aims to simulate electromagnetic field-circuit coupled systems.Firstly, frequency domain surface integral equation method is used to analyze linear lumped elements loaded antenna problems, including classical Delta-gap voltage source feeding model, resistance, capacitance, inductance and other lumped elements loaded dipole antenna problems.Then, electromagnetic field-circuit coupled algorithm based on time domain surface integral method and time domain volume surface integral equation are studied in this paper. The building of marching-on-in-time based time domain integral equation is discussed, and circuit equation based on modified nodal analysis is introduced. The microwave field-circuit coupled system equation is built up, and applied to analyze linear lumped element loaded microwave antenna and circuit problems.Next, nonlinear lumped element loaded electromagnetic field-circuit coupled system equation is studied. With Newton iteration method, nonlinear equation is solved. A modified solution method of time domain nonlinear coupled system is introduced. The equivalent circuit models of Schottky diode, PIN diode and field-effect transistor are described in detail. The electromagnetic field-circuit coupled equation of microwave nonlinear element loaded circuit problem is established, and its simulation is realized in this paper.In the end, the influence of incident time domain plane wave on the whole field-circuit coupled system structure is taken into consideration in this paper. With the effect of circuit structure and incident wave, electromagnetic field-circuit coupled equation based on time domain integral method is built up. Electromagnetic scattering problems of lumped elements loaded circuit are analyzed and discussed in this paper.