The Research Of Waveguide Discontinuity Problem In Symplectic System

Waveguide discontinuity problem is one of the basic questions of waveguide. It isimportant to determine the energy distribution of incident wave and reflection wavefor designing the kinds of microwave device. With the rapid development ofinformation society, the research on the various waveguides will get rapiddevelopment, and have the broad applied prospect.In this dissertation, we solve waveguide discontinuity problem in symplecticsystem. The details are as follows.(1) Combine with PML absorbing boundary conditions, the waveguidediscontinuity problem is analyzed and solved by using the precise integrationalgorithm as well as the substructures combination by the finite element method.The waveguide can be treated as any substructures in the longitudinal direction,and PML is also treated as a substructure. The cross section of the substructures ismade discrete by using the finite element method. Then the export stiff matrices couldbe calculated by precision integration based on Riccati equations in a Hamiltoniansystem, and the whole waveguide discontinuity problem can be solved by thecombination of substructures. The numerical results of the examples show that themethod is effective. And the disadvantage that the artificial boundary must be faraway from the non-uniform region is overcome by this method. It is more effectiveand stable for the analyses of waveguide discontinuities.(2) The transmission properties of photonic crystal is analyzed and studied insymplectic system.The process of solving one-dimensional photonic crystals in symplectic system isderived minutely, and the program is compiled according to this method. Numericalexample demonstrates that the effectiveness of this method. Many different factorshave important influence on the transmission properties of one-dimensional photoniccrystals, such as the electromagnetic wave incident angles, the cycle of dielectric layer,the thickness of dielectric layer and the proportion of thickness. Based on this method,we discuss respectively the influences. In addition, we combine with PML absorbingboundary conditions to analyze the problem of photonic crystals structures inrectangular waveguide. the result of example also shows the validity of this method.(3) The analysis software based on MATLAB is developed and designed for theproblems of dielectric discontinuities in waveguide.Based on the theoretical analysis and numerical calculation, the analysis softwareis developed and designed for the problems of dielectric discontinuity waveguide.Through entering the parameters of the waveguide directly, users can analyze thetransmission of dielectric discontinuity waveguide, and obtain the reflection coefficient, transmission coefficient and the loss ratio of the incident power, etc. Theresults can be display in the form of graph intuitively. Thus the analysis of thetransmission characteristics is quicker and more convenient. The whole system isfriendly and open. The interfaces are conveniently used by different users.