I am new to mixer circuit design, but I need to build a simple mixer that will downconvert a 10 GHz signal to a DC to 3 kHz signal. I know I can do this with a schottky diode and lowpass filter to isolate the lower harmonic (f-IF = f-RF - f-LO). The problem is that the RF signal will be in the uV range. Will mixing still work with a weak signal or do I need to amplify it? I read somewhere that the RF signal should be much lower than the LO signal such that the diode transconductance is affected by the LO signal only, but how low is too low? Thanks for your help!