LTSpice is very Cool

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Mikebits

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The more I play with LTSpice the more I love it, it is very powerful indeed. I recently discovered (By reading the included manual), that you can do S-parameters, which is fantastic
I built a RF power splitter/combiner and been comparing actual test results to simulations, and boy they sure come close. I want to do a little write up later after I compile all my test results and put it down on paper. Oh by compare, I mean transient analysis not the S-params as I do not have equip for that. But here is a shot using the s params.

 
When doing filters and RF things:
I add the wire resistance to an inductor/transformer. I also add parallel capacitance to get the self resonance right.
Large capacitors also have self resonance. I add the ESR and ESL to make the part simulate better.

Normally you don't have to be so picky. If you want to know the bandwidth of a splitter you need to know everything about the transformer.
 

Yeah, when I was setting up my design I tried to get as much of that data as I could. I used a program from Amidon (see image) which helps calculate the parasitics. I used a T50-6 iron powder core, so I used the values provided in the program. I tested my resonant point using a sig gen and 50Ω resistor and swept for a peak. I am included a page from my notebook.

 
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Note: My reference app was from Mini-Circuits:
AN-20-001 Rev.: B M150261 (04/15/15) File: AN20001.W61
This document and its contents are the property of Mini-Circuits.

**************Edit****************************************
Oops, forgot to include the link.
Mini-Circuits Appnote
 
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