An Implicit Hybridizable Discontinuous Galerkin Time-Domain Method to Solve S-parameters in the Waveguide Port

It is important about energy coupling for the waveguide port. In order to compute its transmission characteristics, an implicit hybridizable discontinuous Galerkin time-domain (imHDGTD) method is proposed to solve the S-parameters. Compared with classical discontinuous Galerkin time domain (DGTD) method, the imHDGTD method has a fewer number of degrees of freedom (DOFs). By using the matrix solving technology, the imHDGTD method can accelerate the iterative solutions of the global linear system when using the implicit time scheme. Since the waveguide excitation source takes the field disappearance in the computational region as the sign of iteration termination, the imHDGTD method can effectively shorten the computational time. What's more, in order to reduce the numerical reflection caused by space truncation, the waveguide port is truncated with the perfectly matched layer (PML) in the imHDGTD method. Some tests show the S-parameters of the imHDGTD method are consistent with the results of DGTD. When the computational region is made up with locally refined meshes, the time step of the imHDGTD is larger than the DGTD method.