HFSS Wave Port Sizing

[ngox]

Hi, I've read some threads on here about wave port sizing, and seems like the approach is to increase wave port size, and then check the solved ports so that it can capture all propagating modes, correct? However, for the structure I am simulating, the physical location of ports is very close to one another, so it is a little difficult to increase the size of the ports beyond 1.5 times the width of the metal. If anyone has advice on how to go about sizing the ports in this scenario it would be appreciated. Thanks.

 

[thatyang]

I have same question about the port sizing. However, I guess the size is not necessary for 1.5 times but must be great than the sides of the antenna.
What do you think guys?

 

[PlanarMetamaterials]

Have the waveports cover all relevant conductors, then excite the proper number of modes.

If the ports are close enough that they are coupled anyways, you'd want to model this coupling.

 

[ngox]

Thanks for the responses. Is there some general rule of thumb for determining how large the waveport needs to be when doing this? Right now I am just visually inspecting the Port Field Display and just sizing the wave port larger than the ends of the field display.

 

[PlanarMetamaterials]

Is there some general rule of thumb for determining how large the waveport needs to be when doing this?

It depends on the mode. For a microstrip mode, a good rule of thumb is you want the waveport to cover four times the microstrip width and three times the dielectric height. In general, I don't think there's much of an issue with erring on the side of a larger port, except for the possibility of exciting the wrong mode.