Waveguide Model

The Waveguide model is a semi-analytical model that simulates propagation in an ideal waveguide for a certain length.

This model is only valid for components with 2 ports with equivalent profiles. The S matrix and transmission coefficient between ports are modeled as:

$S = \begin{bmatrix} 0 & t \\ t & 0 \end{bmatrix} \\ t = \exp\!\left(i \frac{2 \pi f}{c_0} n_c L\right)$

Note that, reflections are zero for both ports in this model.

The complex propagation index $n_c$ and the propagation length $L$ are defined in the model settings. If unset, the propagation index will be automatically calculated based on the port profile using a mode solver run. The propagation length can also be left empty, in which case the distance between the 2 component ports is used, assuming a straight waveguide.

Multimode ports

In the case of multimode ports, if $n_c$ is specified, it must be a sequence, with one value for each por mode.

All cross-coupling coefficients are zero in the Waveguide model, i.e., it does not include any mode mixing.