Low Phase Noise Amplifier and Oscillator Using Feed-Forward Technique at 10 GHz
Archita Hati, Craig W. Nelson, David A. Howe
We discuss the performance of a feed-forward amplifier (FFA) at 10GHz. The feed-forward method is primarily used to suppress intermodulation distortion in amplifiers to suppress up-converted near-DC noise. The main amplifier in this configuration is a low-noise array of eight amplifiers in parallel and having a phase noise of 165 dBc/Hz at f= 10 kHz. By implementing a feed forward scheme, we are able to suppress this noise as well as close to carrier noise, by at least another 10 dB. This improved performance surpasses that of other present low noise microwave amplifiers. We discuss this exceptional performance in the context of trade offs with other amplifier properties and specifications. We also construct a 10 GSz oscillator using an air dielectric resonator and the FFA as the loop amplifier. The phase modulated (PM) noise of this particular oscillator is either better than or comparable with the PM noise of several classes of commerical oscillators. Additionally, the AM noise performance is superior to existing oscillators.
IEEE International Frequency Control Symposium
June 5-7, 2006
Proceedings of the IEEE International Frequency Control Symposium