Low-phase-noise surface-acoustic-wave oscillator using an edge mode of a phononic band gap

TL;DR

This paper presents a compact, low-phase-noise 1-GHz surface acoustic wave oscillator on lithium niobate, utilizing phononic crystal bandgap-edge modes to optimize quality factor and minimize phase noise for integrated microwave applications.

Contribution

It introduces a novel SAW oscillator design that leverages phononic bandgap-edge modes to achieve low phase noise and small footprint at microwave frequencies.

Findings

Achieved a phase noise of -132.5 dBc/Hz at 10 kHz offset

Demonstrated a 0.05 mm² footprint for the SAW resonator

Achieved an overlapping Hadamard deviation of 6.5×10⁻¹⁰

Abstract

Low-phase-noise microwave-frequency integrated oscillators provide compact solutions for various applications in signal processing, communications, and sensing. Surface acoustic waves (SAW), featuring orders-of-magnitude shorter wavelength than electromagnetic waves at the same frequency, enable integrated microwave-frequency systems with much smaller footprint on chip. SAW devices also allow higher quality (Q) factors than electronic components at room temperature. Here, we demonstrate a low-phase-noise gigahertz-frequency SAW oscillator on 128{\deg}Y-cut lithium niobate, where the SAW resonator occupies a footprint of 0.05 mm$^2$. Leveraging phononic crystal bandgap-edge modes to balance between Q factors and insertion losses, our 1-GHz SAW oscillator features a low phase noise of -132.5 dBc/Hz at a 10 kHz offset frequency and an overlapping Hadamard deviation of $6.5\times10^{-10}$ at an analysis time of 64 ms. The SAW resonator-based oscillator holds high potential in developing low-noise sensors and acousto-optic integrated circuits.