Dual-Mode Resonator and Switchless Reconfigurable Oscillator Based on Piezoelectric AlN MEMS Technology

For the first time, this work demonstrates a switchless dual-frequency (472 MHz and 1.94 GHz) reconfigurable CMOS oscillator using a single piezoelectric AlN microelectromechanical-systems resonator with coexisting
S
0 and
S
1 Lamb-wave modes of vibration. High performance (high quality factor
Q
and electromechanical coupling factor
k
_t
²
for a resonator and low phase noise for an oscillator) has been achieved for both the resonator and oscillator in terms of dual-mode operation. In particular, 1.94-GHz operation has the best phase noise performance at 1-MHz offset when compared with all previously reported CMOS oscillators that work at a similar frequency.