Low phase noise oscillators above 1 GHz utilizing hermetically sealed all quartz resonators and harmonic extraction

A compact hybrid SAW oscillator with an output frequency of 1.48 GHz, low aging rate, and low phase noise was realized by using the various technologies developed for SAW devices and a unique second-harmonic extraction technique. Bandpass filters are used to select the desired harmonic for subsequent amplification and delivery to a load. The usual 6-dB-per-octave degradation of phase noise with increasing center frequencies is applicable to the higher harmonics, just as it would be if the fundamental were multiplied in external circuitry. This principle has been demonstrated at output frequencies as high as 2.25 GHz