Frequency Reference For Crystal Free Radio

Tech ID: 25675 / UC Case 2016-108-0

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 10,727,886 07/28/2020 2016-150
United States Of America Issued Patent 10,511,289 12/17/2019 2016-108

Additional Patents Pending

Brief Description

Wireless sensors and the Internet of Things (IoT) have the potential to greatly impact society. Millimeter-scale wireless microsystems are the foundation of this vision. Accordingly, to realize this potential, these microsystems must be extremely low-cost and energy autonomous. Integrating wireless sensing systems on a single silicon chip with zero external components is a key advancement toward achieving those cost and energy requirements. 

Almost all commercial microsystems today use off-chip quartz technology for precise timing and frequency reference. The quartz crystal (XTAL) is a bulky off-chip component that puts a size limitation on miniaturization and adds to the cost of the microsystem. Alternatively, MEMS technology is showing promising results for replacing the XTAL in space-constrained applications. However, the MEMS approach still requires an off-chip frequency reference and the resulting packaging adds to the cost of the microsystem. 

To achieve a single-chip solution, researchers at UC Berkeley developed: (1) an approach to calibrating the frequency of an on-chip inaccurate relaxation oscillator such that it can be used as an accurate frequency reference for low-power, crystal-free wireless communications; and (2) a novel ultra-low power radio architecture that leverages the inaccurate on-chip oscillator, operates on energy harvesting, and meets the 1% packet error rate specification of the IEEE 802.15.4 standard. 

Suggested uses

- Industrial Internet of Things (IoT)

- Environmental Monitoring

- Integrated Flight Systems

- Unmanned Aircraft Systems (UAS)


- Low cost due to zero component, on-chip integration;

- Energy autonomous from energy harvesting due to low power;

- Compliant with IEEE standard;

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