I have nice test Jig for VHF and maybe higher. I used 1206 pads for short, open and load. (and through). But for that I needed to solder and desolder pads repeatedly and then the DUT too.
What if I build 5 or more similar jigs on a same PCB, one permanently open, one permanently shorted, and so on  Does it work, or Is FR4 good enough that values are equal across the whole board. One jig is small, but it is better to several places for DUT.

On Sun, Mar 19, 2023 at 07:58 PM, Leif M wrote:

>
> I have nice test Jig for VHF and maybe higher. I used 1206 pads for short,
> open and load. (and through). But for that I needed to solder and desolder
> pads repeatedly and then the DUT too.
> What if I build 5 or more similar jigs on a same PCB, one permanently
> open, one permanently shorted, and so on  Does it work, or Is FR4 good
> enough that values are equal across the whole board. One jig is small, but
> it is better to several places for DUT.

There are several parameters of FR4, like dielectric constant, that will vary with manufacturer but if you lay out the the jigs on the same PCB I suspect that you will be fine for VHF.   I assume you are not measuring the properties of the SOL loads with a high end VNA and using these parameters during the cal procedure so you have other uncertainty issues anyway.

Roger

You are probably right, or at least we agree. (=you are right?)