Acoustic whispering gallery mode resonator with Q > 109,000 at 515MHz

Abstract

A capacitive-gap transduced micromechanical resonator design based on an acoustic whispering gallery mode (WGM) constructed in micro-crystalline diamond has achieved a Q >;109,000 at 515MHz, posting an f·Q product of >;5.6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> . The key to this performance is anchor-loss nulling by the WGM, as evidenced by comparison of Q values between radial-contour modes and WGM ones on the same disk device, where a 2-3× enhancement of Q is observed. Q's exceeding 100,000 should enable unprecedented RF front-end frequency selectivity and low phase noise oscillators for future communications.