Frequency stability of high-overtone bulk-acoustic resonators

Abstract

The results of phase noise measurement for high-overtone bulk-acoustic resonators (HBARs) for use in high-performance oscillators, operating at 640 MHz with insertion losses of 10-15 dB and unmatched Qs greater than 110 K are reported. Noise measurements made on these resonators with input drive levels of 16 dBm have shown self-noise levels of S(y)(f=100 Hz)=8.0x10(-26) for 1/f noise which represents state-of-the-art for a UHF resonator.

Parameter characterization of high-overtone bulk acoustic resonators by resonant spectrum method

“…These devices, however, fall short in accomplishing the required performance because of a failure to operate at high enough frequencies or insufficient Q-value at the high frequencies. It was reported that the Q-frequency product exhibited by the types of VHF BAW and UHF SAW resonators is often used on the order of 12 · 10 12 and 6 · 10 12 , respectively [1]. On the other hand, high-overtone bulk acoustic resonator (HBAR) consisting of a piezo-film with two electrodes on a substrate with a very high Q value, exhibits a Q-Frequency product more than 10 14 [2][3][4].…”

Interfacing planar superconducting qubits with high overtone bulk acoustic phonons

“…Recently, several experiments have successfully integrated qubits with surface acoustic wave resonances in piezoelectric substrates [30][31][32][33][34], showing much higher Q values. An alternative option, discussed in the current work, is offered by highovertone bulk acoustic wave resonators (HBAR) where the mechanical energy is diluted in a low-loss substrate [35][36][37][38][39][40]. These systems have been investigated because they show promise as a clock source due to their high Q values up to ∼ 10 5 at GHz frequencies at ambient conditions.…”

Characteristics of the unique modes in HBARs

“…Fig. 2 The impedance magnitude of a HBAR (2). Resonance frequencies and the spacing of the resonance modes Based on the definition of the IEEE standard [9], the parallel resonant frequency of a single piezoelectric plate corresponds to the maximum resistance, which is the real part of the impedance of the resonator.…”

“…However, highovertone bulk acoustic resonator (HBAR) consisting of a piezoelectric thin film on a very high-Q substrate, which needs not exhibit piezoelectricity, exhibited a Q-f product more than 14 10 . HBAR is an attractive candidate for very high-stability frequency control/selection [1][2][3][4].…”

“…In an HBAR, there are a few tens to a few hundreds modes appeared in its frequency spectra, for example, for the one in [2], the resonance frequency spacing of the substrate is 2.5 MHz, and the fundamental mode of the ZnOfilm is 640 MHz, so its mode order of the operating mode should be 257. In application of fixed frequency oscillators, however, only one mode will be used.…”