Wave port

[dot-cross]

Added support for waveports. Modified palace_demo_cpw notebook to simulate and plot both lumped and waveports.

[dot-cross]

[vvahidd]

@dot-cross why do you think S21 for waveport is 4dB more lossy? this simple cpw line should be very close to no loss. can you look at what mode is being excite in the waveport? maybe it's the wrong mode

[dot-cross]

@dot-cross why do you think S21 for waveport is 4dB more lossy? this simple cpw line should be very close to no loss. can you look at what mode is being excite in the waveport? maybe it's the wrong mode

Not sure why is 4dB more lossy. The mode is set to one, which by Palace documentation correspond to the biggest wave number.

[dot-cross]

This is for mode 2 @vvahidd

[mdmaas]

Maybe the waveport region should be made larger? I mean, perhaps the 2D eigenvalue solver is converging to the correct numerical solution, but the domain where the problem is defined (which is a truncation of the real unbounded domain) is too small. Maybe even the airbox is not large enough. For example, I know that in antenna problems we need an air region that is at least $\lambda/2$ large.

[mdmaas]

We could also add the visualization of the mode for verification purposes.

For an example reference, here I have a CPW simulation where the airbox seems to be too small, as the eigenmode is non-zero at the top:

I think that for this PR just making the domain (and the waveport) large enough should be sufficient, but eventually we need to bring the viz server back to life :-D

[dot-cross]

Lumped port displaced inside the board. Margin set to zero for meshing in both cases.