Sub-THz CMOS Molecular Clock with 43ppt Long-Term Stability Using High-Order Rotational Transition Probing and Slot-Array Couplers

📋 论文概要

该论文提出了一种基于亚太赫兹CMOS的分子时钟，利用高阶旋转跃迁探测和槽阵列技术，实现了43ppt的长期稳定性，解决了传统晶振/MEMS振荡器长期老化与温度敏感性问题，适用于5G基站等高精度时间同步场景。

💡 主要创新点

• 首次在CMOS工艺中利用亚太赫兹频段的高阶旋转跃迁（如CO分子的J=3→2跃迁）作为频率参考，实现超高长期稳定性。
• 提出槽阵列天线结构，增强分子吸收信号的信噪比，降低系统功耗和面积。
• 通过锁相环和分子吸收谱线锁定技术，将时钟频率稳定度提升至ppt级别，优于传统OCXO/OCMO。

🏷 关键词

📄 原文摘要

Future ultra-broadband and low-latency radio access networks pose stringent specifications for time synchronizations. For 5G base stations, inter-site timing error should be <130ns for carrier aggregation and <10ns for high-accuracy positioning [1], requiring a 10-10-level relative drift for a 1min clock holdover. Meanwhile, massive deployments of compact access nodes also make small size, power, and cost indispensable for clocks. Oven-controlled crystal/MEMS oscillators (OCXO/OCMO) with moderate cost are currently used. But, their resonators exhibit long-term aging and high-temperature sensitivity (-31ppm/K for MEMS resonators), hence requiring up to a watt-level heater power for temperature stabilization. Referencing clocks to invariant physical constants well solves the drifting issue. To this end, chip-scale atomic (Cs or Rb) clocks (CSACs) [2-4] have achieved outstanding stability, low power (120mW in [3]) and

👥 作者与机构

Cheng Wang, Xiang Yi, Mina Kim, Ruonan Han

Massachusetts Institute of Technology, Cambridge, MA