<CST> Defining Ports and B.C. for a power splitter <

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Pushhead

Joined: 19 Jan 2005
Posts: 195
Helped: 8

02 Jun 2005 22:13 <CST> Defining Ports and B.C. for a power splitter <

Hi All,

Background story:

I'm designing a 2-way power splitter and would like your comments/advices about some issues i've encountered.

First of all, the splitter is a "standard" wilkinson power splitter, using a 50 ohm microstrip line on a grounded dielectric slab.

After building th model, adjusting the mesh and defining waveguide ports, i've conducted several simulations, each with different Boundary Conditions (B.C.).
1st. All electric BC ( as CST recommends for this type of models )
2nd. All open BC (Tight)
3rd All open expanded,
4th All electric with full de-embedding.

The problem :

Each simulation gave different results from the others !
I understand that there's a difference between theory and "real world" and some optimization has to b made, but....the same splitter resonates at 4GHz in the 1st and at 5GHz at the 2nd simulation....

Can you help ?

BTW: I made sure same mesh density and port impedance is kept , especially at the 3rd simulation.

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svarun

Joined: 31 Mar 2002
Posts: 280
Helped: 7
Location: In the warm company of God's most exquisite creation - The Tiger

04 Jun 2005 14:16 Re: <CST> Defining Ports and B.C. for a power splitter

Obviously BCs do matter and obviously changing the BCs affect the resonant frequency. In real world the splitter would go into a package and hence CST recommends using Perfect E BCs. I do not have any problem with your results.

-svarun