Chang Chin-Yu, Yu Ya-Ching, Lee Zhi-Qiang, Li Ming-Huang
IEEE Trans Ultrason Ferroelectr Freq Control. 2024 Oct;71(10):1314-1323. doi: 10.1109/TUFFC.2024.3453432. Epub 2024 Oct 10.
In this work, we investigate, for the first time, a low phase noise and wide tuning range voltage-controlled surface acoustic wave oscillator (VCSO) based on a lithium niobate on sapphire (LNOS) low-loss acoustic delay line (ADL). The thin-film LN/SiO2 bilayer acoustic waveguide, together with the single-phase unidirectional transducer (SPUDT) design, is key to attaining low insertion loss (IL) by enhancing energy confinement and directionality. Based on a high-performance ADL with an IL of only 5.2 dB, a fractional bandwidth (FBW) of 5.38%, and a group delay of 110 ns, the VCSO is implemented by commercially available circuit components using a series-resonant topology. The LNOS ADL oscillator operates at 888 MHz, showcasing a low phase noise of -94.1 dBc/Hz at 1-kHz offset and a root-mean-square (rms) jitter of only 30.26 fs (integrated from 12 kHz to 20 MHz) while only consuming 16 mA of supply current. Featuring a wide frequency tuning range of 6630 ppm, the proposed VCSO is a promising low-noise, low-power, and high-frequency timing device for emerging applications.Index Terms- Acoustic delay line (ADL), jitter, lithium niobate (LN), oscillator, phase noise, surface acoustic wave (SAW), thin film.skiptabldblfloatfix.
在这项工作中，我们首次研究了一种基于蓝宝石上铌酸锂（LNOS）低损耗声延迟线（ADL）的低相位噪声和宽调谐范围压控表面声波振荡器（VCSO）。薄膜LN/SiO₂双层声波导与单相单向换能器（SPUDT）设计相结合，是通过增强能量限制和方向性来实现低插入损耗（IL）的关键。基于一种高性能ADL，其插入损耗仅为5.2 dB，分数带宽（FBW）为5.38%，群延迟为110 ns，该VCSO采用串联谐振拓扑结构，由市售电路元件实现。LNOS ADL振荡器工作在888 MHz，在1 kHz频偏处展现出-94.1 dBc/Hz的低相位噪声，均方根（rms）抖动仅为30.26 fs（从12 kHz到20 MHz积分），而功耗仅为16 mA电源电流。所提出的VCSO具有6630 ppm的宽频率调谐范围，是一种适用于新兴应用的有前景的低噪声、低功耗和高频定时器件。关键词——声延迟线（ADL）、抖动、铌酸锂（LN）、振荡器、相位噪声、表面声波（SAW）、薄膜。
