FET Mixer

Hi All,

I'm using a MESFET as a self-oscillating mixer. Normally, i operate the FET at Vds=3v and Vgs=0v. However, when I turn down Vds =2V, gain of the IF actually increases.... what is happening? I can't seem to fit this behaviour to any theory since (when looking at ) Ids remains almost constant. Can't find info on g vs Vds behaviour too....

Many Thanks!

The mixing action depends upon nonlinearities. At lower supply levels there are probably more nonlinearities for a given input signal level.