Chenxin Zhu

Ph.D, Chinese Academy of Sciences, Institute of Microelectronics, with Prof. Ming Liu, 2012

Email: cxzhu AT stanford DOT edu

Wearable Smart Sensor System

Wearable electronics has drawn remarkable research interest for potential applications in wearable physiological monitoring and diagnosing [1], electronic skins for prosthesis and soft robotics [2], and human-machine interfaces [3].
As most mixed-signal electronic systems, the stretchable smart sensor system can be divided into three main sections [4] -– the analog transducer that acquires and converts physical information to electrical outputs, the analog signal processing circuits, and the digital signal processor (Figure 1).

Figure 1. Wearable smart sensor system

My research focuses on developing stretchable sensors that can conformably adhere with human skin or tissues for collecting reliable data free from motion artefacts. An ideal stretchable sensor is expected to be sensitive only to the measurand, while in practice, it will suffer from cross-sensitivities with strain or other physical parameters. To reduce the effect of cross-sensitivity on the accuracy of the sensor output, it is beneficial to process the sensing signal locally and realize correction of the output 5. A local amplifier with strain-insensitive performance is also desirable for the weak analog signal from the sensor. The circuit design for conventional smart sensors has been introduced to realize the robust stretchable sensors with the fabrication platform of stretchable and flexible electronics. Considering the circuit complexity, the mixed signal processing part will be developed by CMOS chips 6. The wearable smart sensor system will be demonstrate with the developed stretchable sensors and interface electronics.

[1] D.-H. Kim et al., Epidermal electronics. Science 333(6044), 838, 2011.
[2] B. C. K. Tee et al., A skin-inspired organic digital mechanoreceptor. Science 350(6258), 313, 2015.
[3] S. Lee et al., A strain-absorbing design for tissue–machine interfaces using a tunable adhesive gel. Nature Communications 5(5898), 2014.
[4] W. Xiong, Analog signal processing circuits in organic transistor technology, 2010.
[5] C. Zhu, Stretchable temperature-sensing circuits with strain suppression based on carbon nanotube transistors. Nature Electronics 1(3), 183, 2018.
[6] W. Gao et al., A fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis. Nature 529, 509, 2016.