XFdtd offers modal and nodal waveguide interfaces.
XF offers two waveguide interfaces for exciting a broad range of waveguide structures and transmission lines. Together, XF’s Modal Waveguide capability and Nodal S-parameters provide more accurate solutions for waveguide excitations and allow XF output to be passed to a circuit solver for post-processing.
XF’s Modal Waveguide Interface is well suited for classic rectangular and circular conducting pipes. Based on the waveguide’s shape and associated materials, XF determines the supported modes, then applies an impedance matched modal excitation directly to the waveguide structure. One or more higher order modes -- such as TE11, TE21, TM11, and TM21 -- can be defined, allowing S-parameters to be computed between them.
XF’s Nodal Waveguide Interface computes single-ended S-parameters for transmission lines, such as microstrips, differential pairs, and multi-pin connectors, providing enhanced analysis options for PCB design and signal integrity. The interface allows users to select transmission line pins and apply a user-defined reference impedance, thus creating an impedance mismatch at the source. Renormalized S-parameter values that exhibit the mismatch are computed during the simulation and can be exported for analysis in a circuit solver.