Measuring a splitter using the Palmer method

[wickli...@gmail.com]

Hello everyone

I am working on measuring a power splitter.

According to what I found in this group as well as in the VNA Tools documentation, there are two main ways to go about this: The first being the Juroshek method, which seems to be problematic at lower frequencies and therefore is not fully recommended.

The second seems to be the palmer method, which is also recommended by metas. Now, according to the palmer example in VNA Tools, it looks like I'll get the equivalent reflection coefficient as S22 and S33 and the transmission tracking as S21 in the calculated file, is this correct?

Is there any way I get the S-Parameter (mainly S12 and S13) of the splitter out of this?

Or how does metas measure the S-parameter?

Thanks in advance

Patric

[Tuomas Haitto]

Hi Patric,

I have two port VNA

I have used Palmer method also and it working well. If I want measure tracking, then simply put VNA port 1 to power splitter Input and VNA port 2 to the splitter's output arms 2 and 3. Always another output arm which leave open I terminate with very good matched load (RL <40dB on entire frequency range). After measurements I compute difference between Input--Output 2 and Output 3. For my purposes it has been enought accurate method.

In real life measurement situation power splitter arms might connect cables, connector's etc, so even splitter is characterized very sophisticated then bigger match errors surely comes what is connected on splitter ports. Those things can change splitter balance rather significantly and should take then considiration also.

Tuomas      

[wickli...@gmail.com]

Dear Tuomas

Thanks for your answer.

I was thinking that this would be the answer.

S12 and S13 are not very important to us, but measuring them every now and then, just to get a rough estimate is still not a bad idea in my opinion.

I haven't found time to try palmer, but I will do so as soon as possible :)

Patric