HFSS waveport setting for calculating port impedance with antipodal vivaldi antenna

[rashford]

Hello guys, I'm trying to calculate port impedance of the antipodal vivaldi antenna(AVA).
But as you know, AVA has metal-substrate-metal structure.
Each metal plates are for radiating, but at the balun stage, the one has a purpose for ground the voltage.
So, I have difficulty on setting the waveport for the antenna.

For example, we can set waveport for microstrip structure touch the ground plate. Because it has larger size than the stripline.
But my antenna ground plate has little bit larger size than top metal plate, so if I set the waveport touching the ground plate, it will ignore fringing field between the plates.

If someone has knowhows how to set the waveport well for the antipodal vivaldi antenna structure, plz help me.

 

[PlanarMetamaterials]

I think you need to provide more details on the exact type of feedline you're using, but the instructions for using waveports are typically always the same:

1. Size the port so that it is large enough to capture nearly all (>99%) of the modal fields.
2. Size the port so that it is small enough that your desired mode(s) will not couple with higher-order waveguide modes supported by the port.

 

[rashford]

I think you need to provide more details on the exact type of feedline you're using, but the instructions for using waveports are typically always the same:

1. Size the port so that it is large enough to capture nearly all (>99%) of the modal fields.
2. Size the port so that it is small enough that your desired mode(s) will not couple with higher-order waveguide modes supported by the port.

Actually, I will utilize waveport for my antenna, Antipodal Vivaldi Antenna. It has not general feed shape like my attatched image. It has two different size metal plate across the dielectric substrate (I set the substrate transparent). So I have difficulty on setting the waveport.
Anyway, your setting condition will be important on setting the port. Thank you so much.