driven modal
I would like to know what is the difference between using a driven modal solution and using a driven terminal solution.
I simulate a current loop, I have used each solution type, and the results are differents. I don't understand why!
Thanks in advance for your help!
There are three solution types in HFSS(Driven Modal,Driven Terminal Modal and Eigenmode).You can choose the one which is most suitable for your EM problem before you start to simulate it.As what is explained in the column of the keyword "Selecting the Solution Type" in HFSS Oline Help,Driven Modal is suitable for passive high frequency structue which is driven by a "source",such as waveguide,microstrip, transmission line and so on.In this solution type,HFSS caculates S-matix which is based on modal and the matrix is expressed in refelective and incident power(1W average power of time domain).And Driven terminal Modal caculates S-matix which is based on terminal and the matrix is expressed in refelective and incident voltage or current on the terminal(the voltage and the current are caculated respectively by integrations of E and H along the defined integration line and the circumference of the defined port).Eigenmode is used for caculation of the eigenmode of the structure and resonant frequency and its corresponding field.
Thre results must be the same as far as your model is a current loop.
Hello!Did you mean "as far as" "if" in you lastest reply?And whether you have some more experiences or suggestions over the topic?
This also puzzled me. I think the essential difference or emphasis between driven modal and driven terminal is using modal based S-matrix or terminal based S-matrix. As we know, for some structures, there is no easy task to define voltage or current, so we need modal based S-matrix. Then for such kind of structures, we need to use modal based S-matrix. For structures operating with TEM mode, we may use either solution type: driven terminal or driven modal. As a result, it can be inferred that, as for microstrip antenna, the simulation results from terminal and modal type are very close. While there is a bit larger difference between results from terminal and modal type for loop antenna, however, still can be neglected. And this inference has been verified by my simulation.
Driven Modal and Driven Terminal modal are respectively suitable for different EM problem.And they also suitable for the same EM problem.But they express very different meanings though sometimes they share some quite similar results.Driven Terminal Modal calculates the terminal-based S-parameters of multi-conductor transmission line ports. The S-matrix solutions will be expressed in terms of terminal voltages and currents.The two different solution types have different result report type and style.