RF component measurement

Hi,
I would like to find out how I can measure the S parameters of a RF transistor/amplifier and compare them agaist the datasheet given by the manufacturer. Would it suffice for me to build a PCBA complete with the required dc biasing circuit and connect a pair of SMA connectors at the input and output for connection to the network analyser for the S parameter measurements?
I don't suppose I will need to add any matching circuits at the input and output of the transistor/amplifier as the whole idea is to measure the input impedance (S11) and output impedance (S22) but without the matching circuits, will I get a good measurement of the gain (S21)?

Thanks.

I suggest to review the methods and special test fixtures for device S-parameter measurement offered by major vendors, e.g. Agilent to get an idea of the involved effort.

Basically you can use your own test fixture, including bias circuits, if you are able to perform the necessary open, short and load calibration at the transistor terminals. Although calibrated, the imperfections of the test fixture will increase the total measurement error.

To use an identical fixture (as manufacturer's) would be a lucky guess, especially at microwave frequencies.
But the problem is, most of the RF chip manufacturers use expensive probe stations to measure S-paramaters. And this would be very hard to follow.

Probe Station: RF Signatone Probe Stations, microprobing equipment, and microwave probers

For packaged transistors and amplifiers, it's not that complicated to measure S-parameters for design purposes.

You would indeed build a test PCB for the device under test (without matching) and the corresponding TRL calibration standards. For the bias, a commercial Bias-T device might be better (wide band without resonances) than homebrew biasing.

I have done this a couple of times for devices up to 26GHz and it works fine, as long as you want to use the data for design. However, the results will not always agree with manufacturer data because your grounding is different (other PCB thickness -> other via lengths etc.) or simply because the manufacturer's measurement conditions are unknown.

---------- Post added at 13:31 ---------- Previous post was at 13:26 ----------

SOLT calibration might be difficult indeed for calibration of PCB test fixtures. You might want to try TRL instead.

Yes, but it's not necessarily supported by the VNA and may require external calculations.

Thanks, everyone for your invaluable feedback.

FvM and volker_muehlhaus mentioned about the use of bias tees for the setup, I was wondering if I should have one (bias tee) connected to a voltage source to bias the collector and another one connected to a current source to bias the base of the NPN transistor.

Thanks.

Yes, correct.