Help on HFSS stimulation

Hi,

I have some doubt which I hoped you guys could help. Currently I'm using the HFSS 8 to run some stimulation for a finline structure as below. http://www.photoi.org/gallery/showph...cat=500&page=1

Could I ask is it possbile to specify the finline port to be 480Ω to the microstrip port of 50Ω and run a stimulation of it?

Thanks

The port impedances have no influence on your calculation. However, the result does of course. So if you want to view results or export for example the s-parameters you can define any port impedance you want. That is called "renormalisation".
hope it helps. D.

Hi MR D,

Could you explain more in details? Thanks

it is possible to specify any port impedance for a port. hfss calculates the fields regardless of the specified port impedance. of course, if the port impedance doesn't match the line impedance you will have a lot of reflections. if you plot or export s-parameters they will be calculated for the given port impedance (s-parameters are always related to a given impedance).

hope it helps. otherwise please ask more detailed.

D.

hello :

that's depend if you want to analyse it with perfect matching or not .

it's clear that analysing in HFSS is almost independent of return loss , in fact results of computation for Directivity & HPBW & even figure of Pattern may be identical for several variuous quantity of Input Impedance But you must explain more if matching is exactly necessary for you or not . if it not necessary you can use some approximation .