Design, simulation and test of an oscillator suitable for wafer level evaluation of SAW resonator phase noise

In a well-designed BAW or SAW oscillator, the primary contributor to near-carrier, flicker-of-frequency noise should be the resonator itself and not the sustaining stage amplifier. Determination of resonator short-term frequency stability (self-noise) at the wafer level is highly desirable from both the perspective of resonator selection prior to packaging and evaluation of processing conditions resulting in low noise resonators. The objective of this work was to develop a methodology where the flicker-of-PM noise contributions of the sustaining stage amplifier and the resonator could be reliably and independently determined. In addition, the methodology needed to be compatible with and tolerant of coaxial probe connections to on-wafer resonator arrays. The current status is that the results obtained for evaluation of packaged and on-wafer devices are quite comparable.