Discontinuous Galerkin Time Domain Finite Element Method Analysis Of Device Loaded Electromagnetic Periodic Scattering Structures

Periodic structure refers to a structure whose geometry or material changes periodically.Due to its unique electromagnetic characteristics,periodic structure has been widely used in microwave engineering,antenna design and optical engineering.Common periodic structures include frequency selective surface(FSS),energy selective surface(ESS),phased array antenna,photonic crystal,meta-materials,meta-surfaces,etc.Loading a load element on a periodic structure to change the electromagnetic characteristics of the structure is currently a hot topic studied by many scholars.In view of this,modeling and simulation of periodic structures using numerical algorithms is of great significance for studying and analyzing the electromagnetic characteristics of periodic structures loaded by elements.Because discontinuous Galerkin time domain finite element method(DGTD)not only has high accuracy but also can obtain the target broadband information by one simulation,this paper will focus on the electromagnetic scattering of periodic structures loaded by elements based on DGTD method.Firstly,in order to solve the electromagnetic scattering problem of periodic structures loaded by lumped elements,ADER-DGTD method are used to analyze it.The calculation area is divided into two parts: electromagnetic field area and field-circuit coupling area.For electromagnetic field region,Maxwell equations need to be solved.For the field-circuit coupling region,it is necessary to jointly solve Maxwell’s equations and the volt-ampere characteristic relationship satisfied by lumped elements.Using this method,the influence on the electromagnetic characteristics of the structure when the periodic unit is loaded with linear elements such as resistors and capacitors and nonlinear elements such as diodes is analyzed in detail.Secondly,ADER-DGTD numerical simulation algorithm which is suitable for mixed solution of electromagnetic model and semiconductor physical model is proposed,and electromagnetic scattering problem of periodic structure loaded by PIN diode physical model is analyzed.Where,the transient electro-thermal numerical simulation analysis of the PIN diode physical model is realized by solving the drift-diffusion equation and the heat conduction equation satisfied in the semiconductor by using SETD.The process is packaged into subprogram,and the relationship between voltage and current at end of the PIN diode is expressed in the form of implicit functions.The wave transmission performance of the energy selective surface structure and the variation of the internal temperature of the semiconductor device with time under different incident field intensities are analyzed.