Summary: JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 19, NO. 3, JUNE 2010 503
Micromechanical IBARs: Tunable High-Q
Resonators for Temperature-Compensated
Reference Oscillators
Gavin K. Ho, Member, IEEE, Krishnakumar Sundaresan, Member, IEEE,
Siavash Pourkamali, Member, IEEE, and Farrokh Ayazi, Senior Member, IEEE
Abstract--This paper presents a unique capacitive microme-
chanical resonator and oscillator architecture for temperature-
compensated frequency references. The I-shaped bulk acoustic
resonator (IBAR) is designed to have excellent electrical tunabil-
ity for temperature compensation (TC) and dynamic frequency
control. High quality factor and low motional resistance are also
achieved. The applicable range of frequencies is 1­30 MHz, in
which quality factors exceeding 100 000 have been measured.
Resonator metrics, including the electrostatic tuning coefficient,
normalized dynamic stiffness, and relative dynamic compliance,
are introduced. A small-signal resistance in the resonator is re-
ported and explained. This unexpected resistance is beneficial for
oscillator functionality over a large temperature range. The inter-
face IC, inclusive of all blocks for sustaining oscillations and TC,

Source: Ayazi, Farrokh - School of Electrical and Computer Engineering, Georgia Institute of Technology

Collections: Engineering