what's difference of "Driven Modal" and "Driv

In HFSS, there are two different solution types for S-parameters simulation:

Driven Modal and Driven Terminal.

What are the major differences between these two solution types?

Thanks

For single terminal ports, I think there is no difference between them. However, for ports with multiple terminals you will have to use the Driven Terminal

However, in HFSS documentation the use Driven Terminal for TEM excited guides (such as Microstrip lines) and Driven modal for waveguide structures

"Port refinement, process hf3d error: Port 2 does not have a solved inside material on either side"

Does anyone know what is the root of cause of this error? I try to run driven terminal simulation with HFSS 12 but never get it done. If you know the basic that we need to do driven terminal simulation, i would be more than happy to learn from you. Thanks.

Re: what's difference of "Driven Modal" and "

most probably you used waveport. however, the waveport should have radiation boundary or so on one side.

Hi,

You can use both all the time. Driven Terminal is easier to set up for all conditions, so unless you really want modal s-parameter data, I suggest you use driven terminal. Driven Modal for waveguides may give better results for some cases.

The difference may occur in calculating impedance. For the case of a microstrip, Driven Terminal can give better results because the H x dL integral for the loop to find current is done differently for the two cases. For the driven terminal case, HFSS finds the conductors and creates the loop around those conductors. For Driven Modal the loop is around where the wave port is, which may introduce inaccuracy because the H field is only strong around the strip and not everywhere on the port.

Joline.

you shold put some PEC on the back of the port, if it is a waveport.