It should be possible to define multiple wave ports to the same set of boundary attributes with different mode indices, in order to simultaneously postprocess scattering parameters into each of the modes or drive systems with a sum of the different incident mode shapes. The impedance boundary condition with coefficient i k_n \mu^{-1} would have to be chosen for one of the modes (or the average?). For most engineering cases where you care about multiple modes, the k_n should likely be similar for both modes (even-odd, for example).
It should be possible to define multiple wave ports to the same set of boundary attributes with different mode indices, in order to simultaneously postprocess scattering parameters into each of the modes or drive systems with a sum of the different incident mode shapes. The impedance boundary condition with coefficient
i k_n \mu^{-1}would have to be chosen for one of the modes (or the average?). For most engineering cases where you care about multiple modes, thek_nshould likely be similar for both modes (even-odd, for example).