flames4791
Junior Member level 3
![VCO.jpg VCO.jpg](https://www.edaboard.com/data/attachments/59/59632-31c7626fc96d48a5a80041a4e58b7331.jpg)
I have the VCO schematic above. I need a tuning frequency of 2.35G to 2.55G and phase noise to be below -115dbc at 1MHz. Right now I have the Phase Noise at -111dbc. I read somewhere that you can add a capacitor to the drain of the tail transistor to short the AC noise and then add an inductor in series with the transistor and resonate it at 2f0. However, when I tried this it actually made the noise worse. Are there other methods of improving noise? I have minimized the two oscillator transistors already. Any suggestions would be greatly appreciated. Thanks!