DC bias to a device, and measuring the S11 with a VNA... will this damage the VNA?

[lab-lab]

Good morning,

I have to perform some measurements through a VNA. However, I have to bias the diode that is in the device under test. The polarization bias is very low (0.7V)...however, I'm afraid that I can damage the instrument ...
Should I use anything to block the DC from going into VNA!?

May it help if I gave you the model of the VNA I'm using?
Thanks!

 

[Izeek]

Hello,

Please take a look into your VNA's spec or user guide. Generaly it contains dc blocking capacitor (my E5071C - up to 35V), but it will be better to check. Also you can use external DC Block, but you must recalibrate your VNA to remove added amp/phase uncertainty.

 

[lab-lab]

Thanks for the answer... my VNA is the R&S ZVL-6. I really can't find the answer in the specifications. May you check if it has some built-in capabilities that preserve it when performing measurements with an external bias? The DC blocking capacitor is usually inside the VNA or external?
Thanks

 

[FvM]

At most instruments, also ZVL series, there's a text about maximum ratings beneath the test ports that answers your question.

 

[lab-lab]

As a matter of fact, there is written "MAX +27dBm/ 30V DC"....... so it shoudl actually refer to a possible external "in-going signal" that may wonder through the device under test?

 

[lab-lab]

So, what's the use of th so-called power probe!?

 

[Manuel Maritescu]

Hello lab-lab

I am using too a VNA ZVR and to have no problem you can use an external DC block from Huber+Suhner 10-5Ghz/250V.Also , i have maked another calibration (it is necesary).Hope you will success.

Regards