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GiangHu New Member Offline Posts: 1	Balun hspice netlist Nov 13^th, 2004, 9:23am Hi Ken, The balun netlist that you posted in diff testbench should be read as below: The gain=0.5 not 2, if no "transformer" is included. .subckt balun vid vic vi+ vi- E1 5 vic vid 0 0.5 v1 vi+ 5 F1 vid 0 v1 0.5 r1 vid 0 1T E2 6 vi- vid 0 0.5 v2 vic 7 F2 vid 0 v2 0.5 r2 7 6 1u .ends balun Thx GiangHu
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eskiyerli Ex Member	Re: Balun hspice netlist Reply #1 - Dec 31^st, 2004, 8:52am I had noticed the same thing. Ken gracefully changed the netlist. However, I still have my doubts about that circuit. I am getting strange results for S parameters. I think the problem is that the model is not truly reciprocal. Regards, Murat Eskiyerli
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Ken Kundert Global Moderator Offline Posts: 2384 Silicon Valley	Re: Balun hspice netlist Reply #2 - Dec 31^st, 2004, 9:28am Can you quantify the problem. Say by analyzing some ideal circuits for which the S-parameters are known, and then contrasting the results you get versus the results you should get? -Ken
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Ken Kundert

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Posts: 2384
Silicon Valley

Re: Balun hspice netlist
Reply #3 - Jan 2^nd, 2005, 4:12pm

Guys,
I've tracked down a second problem: the gain of the current controlled current sources should be negated. Here is the updated netlist:
Code:

* BALUN
*
* A bidirectional balanced-unbalanced converter.
* Maps between the unbalanced signals �d=1� and �c=2� and the balanced signals �p=3� and �n=4�.
.subckt balun (1 2 3 4)
* Ideal transformer for the positive input
    E1 5 2 1 0 0.5
    V1 3 5
    F1 1 0 V1 �0.5
    R1 1 0 1T
* Ideal transformer for the negative input
    E2 6 4 1 0 0.5
    V2 2 7
    F2 1 0 V2 �0.5
    R2 7 6 1u
.ends balun

I have updated the paper on the site. Thanks for pointing out these problems.

-Ken

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eskiyerli Ex Member	Re: Balun hspice netlist Reply #4 - Jan 7^th, 2005, 9:29am Thanks Ken, I knew there was a problem as the I was getting 6dB S11 instead -6dB at the input, but was too tired to track it. Now, it seems to be working nicely. Thank you, Murat
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eskiyerli Ex Member	Re: Balun hspice netlist Reply #5 - Jan 7^th, 2005, 9:57am I made a mistake in the earlier post. What I meant was that ac signal at the input was +6dB instead of -6dB when matched. Murat
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