An Efficient Scheme of Waveguide Port Modeling Based on Conformal and Nonuniform Mesh for Time-Domain Finite Integration Technique

A general numerical scheme for waveguide port modeling based on the contour integrated theorem (CIT) is proposed to improve the accuracy and efficiency, which is fully compatible with the 3-D time-domain finite integration technique (TDFIT). In this scheme, a compact 2-D finite-difference frequency-domain (FDFD) method with conformal and nonuniform mesh is derived, along with a novel method for accurately applying the perfect magnetic conductor (PMC) boundaries in this method. An improved two-component form is also developed and used in a 2-D eigenmode solver. Then, the positive-negative (P-N) transparent source is improved to be compatible with the TDFIT method based on the CIT for source feeding, and a novel implementation scheme of waveguide port based on a virtual domain suitable for the P-N source is also proposed. Finally, a simplified S-parameter extraction scheme that requires only modal voltage is proposed. Numerical examples are given to validate the proposed numerical scheme, and the results show good accuracy, lower memory consumption, and higher computational efficiency.