Negative Resistance - RF Cafe Forums
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Post subject: Negative Resistance Posted: Sun Sep 16, 2007 9:23 am
Joined: Fri Aug 11, 2006 6:07 am
I'm trying to synthesize a negative resistance to add to a circuit. As far as I know there are three popular ways of doing so:
1. Using a device with negative resistance characteristics (e.g. Tunnel Diode).
2. Using a configuration of OpAmps with feedback that gives a negative resistance when seen from the input.
3. Using a configuration of BJTs, ot FETs.
It is the third method that I'm interested in since I'm working at a somewhat high frequency and I need to be able to integrate the resulting circuit on an IC. I'm specifically interested in making a negative resistance using MOSFETs. I did read a couple of papers that talked about the subject but it was quite general, with no reference to biasing or methods of tuning. While I was able to sucessfully simulate a negative resistance using two MOSFETs, the resulting resistance was quite large (tens of Mega Ohms) and it was unstable when put in a larger circuit.
The resistance I need is S-type, in the range of tens of Ohms. Can anyone point me to where I can get more info on this subject?