Georgy.Moshkin
Full Member level 5
Similarly to
, I am going to use FET as a varactor.
To test this idea I have added FET varactor to the cut near ground vias of quarterwave "finger" resonator. S21 maximum shifted from 5GHz to 9GHz (FET biased at Vgs=-1v). Simple analysis shows, that for simple quarterwave 5GHz resonator frequency will shift to 9GHz after adding 0.4pF series capactior. Does it mean that FET Cgs is around 0.4pF?
The only way to lower frequency back to 5GHz I see is to increase length of quarterwave resonator, which will become almost half-wavelength, is it reasonable?
, I am going to use FET as a varactor.
To test this idea I have added FET varactor to the cut near ground vias of quarterwave "finger" resonator. S21 maximum shifted from 5GHz to 9GHz (FET biased at Vgs=-1v). Simple analysis shows, that for simple quarterwave 5GHz resonator frequency will shift to 9GHz after adding 0.4pF series capactior. Does it mean that FET Cgs is around 0.4pF?
The only way to lower frequency back to 5GHz I see is to increase length of quarterwave resonator, which will become almost half-wavelength, is it reasonable?
