Pre-made alumina circuits

[mattg2k4]

Hi! I'm a grad student at UCSB and I'm working on some source-pull noise figure measurements. I was looking at your diamond saw for alumina circuits. We're trying to (cheaply) get a CPW attenuator that we can probe with 150um GSG probes, so that we can probe it as a verification of our noise calibration and setup (The attenuation and noise figure should be identical).

I was wondering if you know if there exists a cheap alumina substrate that we can buy that has a probe-able 50ohm CPW line which we can cut open and add in some chip resistors to make an attenuator. The line impedance is not even critical as long as the line is short, since we are operating only up to 4GHz. One of the delay lines on our Calibration Substrate would suffice - but that's not something we want to go and mess with.


P.S., I think your radio projects are cool

Edit: Found some Hittite parts that fit the bill, we have to order 10 but it's not too expensive.

[mightyohm]

I sent a link to Tony, hopefully he will respond here. He used to be a grad student at UCSB as well...