I have a 4 port, 50 ohm ENA, and I need to use this to characterize 75 ohm devices.

I cannot afford to invest in a 75 ohm test set, so I need to use the ENA, and the associated 50 ohm cables and Agilent Switches to make the measurement. I also want to continue to use my 4 port ECal Module

I can add minimum loss Pads at the DUT interface to present the proper impedance.

questions::

1.) Can I cal at the 50 ohms interface at the Pad inputs, and deembed the minimum loss pads, and will I get accurate Insertion and Return Loss measurements for the DUT

2.) Will I need to change the port impedance using the Fixture SImulator?

3.) Is there another method for making 75 ohm network measurements using a 50 ohm ENA?

Thanks in Advance,

Ed C

Symtx

I cannot afford to invest in a 75 ohm test set, so I need to use the ENA, and the associated 50 ohm cables and Agilent Switches to make the measurement. I also want to continue to use my 4 port ECal Module

I can add minimum loss Pads at the DUT interface to present the proper impedance.

questions::

1.) Can I cal at the 50 ohms interface at the Pad inputs, and deembed the minimum loss pads, and will I get accurate Insertion and Return Loss measurements for the DUT

2.) Will I need to change the port impedance using the Fixture SImulator?

3.) Is there another method for making 75 ohm network measurements using a 50 ohm ENA?

Thanks in Advance,

Ed C

Symtx

The idea of de-embedding the pad is reasonable, but to de-embed the pad you must have a good S2P file for the pad, and that get's a bit tricky, as it S2P doesn't support mixed impedances. So, you must use a 75 ohm on one side, 50 ohm on the other, and then impedance convert the 75 ohm side to 50 ohm. This also requires a 75 ohm cal kit.

You could also calibrate in 50 ohms, then port extend through the pad using a DC offset of 5.6 (I think, you do the math) fixed offset and then automatic port extension to compute the loss and delay, and then change impedance. This does not require a calkit, and will give good S21 measurements, but very bad S11 measurements. There is NO way to get good reflection measurments with out a cal kit.