torbai
Member level 3
- Joined
- Nov 15, 2011
- Messages
- 67
- Helped
- 15
- Reputation
- 30
- Reaction score
- 13
- Trophy points
- 1,288
- Location
- Harbin,China
- Activity points
- 1,744
I recently designed a S band LNA. It works well in simulation.
However, when I measured it with an Agilent PNA-X VNA, I found it looks weird...
The measured touchstone(s2p) file is linked below... It can be seen that both S11 and S22 is larger than 1 at some frequencies.
I think the VNA is well calibrated, and the output power of both ports are -30dBm which is the lowest level of the VNA.
Is my LNA oscillates?
I've measured it using a spectrum analyzer connected on the output port of the LNA, while a matched load is attach on the input port. And the result is the LNA doesn't oscillate.
However, when I measured it with an Agilent PNA-X VNA, I found it looks weird...
The measured touchstone(s2p) file is linked below... It can be seen that both S11 and S22 is larger than 1 at some frequencies.
I think the VNA is well calibrated, and the output power of both ports are -30dBm which is the lowest level of the VNA.
Is my LNA oscillates?
I've measured it using a spectrum analyzer connected on the output port of the LNA, while a matched load is attach on the input port. And the result is the LNA doesn't oscillate.
Attachments
Last edited: