Comparative Study of Phase Noise in HEMT and MESFET Microwave Oscillators

Several identical X band cavity stabilized MESFET and HEMT oscillators are presented. Their phase noise and some other noise data are reported. Under exactly the same oscillating conditions, the MESFET oscillators exhibit the best phase noise performance not only because of their lower low frequency noise but also because of a better linearity which provides a smaller LF noise conversion in the microwave frequency range.