Need help with impedance measurement in HFSS

[erdem352]

Dear friends,

I have this simple problem that I can not solve. Let's say you have a 3d shape of
any kind. How do you measure the impedance of this shape at some frequency in hfss ?
I have been attaching a waveport and looking for Z in the results but the Z also
depends on Z0 and Z0 is different for different sizes of waveport. I know it might
be so simple and I am missing an easy point but I need help asap.

Thanks a alot.

 

[Azulykit]

Before anyone can begin to help you with a question like this you need to define the boundaries of your problem. In the current state the question is too general and not focused.

Your question is like asking how to design a vehicle without even focusing enough to say if it is for air, water or land transport.

HFSS can calculate the impedance of general 3D shapes and waveports are used to do the calculations.

A way to get started is to go through some of the Ansoft tutorial materials and work those to gain some experience and familiarity with the software.

 

[erdem352]

Thanks for your message.

Let's say i have a cube of some conductor with the side dimension of 2 cm.
How do I find the impedance of this structure at 1 GHZ?
I have been using a waveport but both Z0 and Z depends on the dimensions
of the wave port, that's where I am stacked now.


thanks.

 

[Azulykit]

I would model the transmission line that I intended to use to excite the cube and put the wave port on that. A coax is one candidate. You miy also want to include some sort of ground plane.

 

[grandizer]

In order to calculate the impedance , first u need a ground reference , try to draw another air cube containing your conductor cube , and assign pec to one side of the air box as reference ground while keeping the other 3 like RAD of Perfect H boundary , the other 2 opposite side of the cube will be used for wave port regarding the dimension of the air box to be large compared to the conductor cube.
Hope it will help

 

[erdem352]

Thanks a lot for your help.

I did some simulations with a coax, it's ok for frequencies at some GHz
but HFSS is giving error for low frequency analysis. How can I analyse my
structure at 10 Khz ?

Thanks a lot

 

[Azulykit]

You might want to give some thought to the length of a wavelength at 10 KHz relative to 2 cm.

 

[amirealipour]

u cant measurment impedence of wave port for 3d structure
becuse wave port define on a plane and its imepedence is depend only shape on this
plane
but u can use VSWR in result and relative it impedance