Low-noise x-band oscillator and amplifier technologies: comparison and status

This study compares the phase noise of different classes of oscillators and amplifiers that work at X-band. Best-in-class results are presented based on recent measurements at NIST. In particular, comparisons are made between mature technologies of multiplied quartz, sapphire dielectric in whispering gallery mode (WGM), and air-dielectric-resonator stabilized RF oscillators in contrast to various configurations of optical electronic oscillators (OEO), cavity-stabilized, and atom-stabilized optical-domain oscillators and femtosecond-lasercomb frequency synthesizers. This study also reports the status of classes of low-noise X-band amplifiers, since high-spectral-purity oscillators are constrained by amplifiers to varying degrees. Best-available low-noise X-band commercial amplifiers are compared with new feedforward, feedback, and array-gain test devices. Straight HBT (heterojunction bipolar transistors) and SiGe HBT technologies are compared in terms of phase noise. Results are for an operating frequency of 10 GHz