Fig. 1. Diagram of structure. (a) Structure of R-OMC; (b) R-OMC under microscope; (c) structure of sensor chip; (d) complete sensor chip

Fig. 2. Mechanical simulation of package structure. (a) Pressure from multiple directions; (b) pressure from single direction

Fig. 3. Vertical displacement of bottom layer of PDMS

Fig. 4. Testing system for performance of R-OMCSC

Fig. 5. Characteristics of R-OMCSC. (a) Pressure sensitivity; (b) voltage change of pressure applied at different locations; (c) response time; (d) repeatability; (e) different detection locations in radial artery; (f) pulse waves at different locations of human pulse

Fig. 6. Typical pulse waveform of brachial artery and radial artery

Fig. 7. Dual-channel pulse wave detection method

Fig. 8. Pulse wave preprocessing process

Fig. 9. Grid search results for c and g. (a) SBP model; (b) DBP model

Fig. 10. Output of SVR prediction model. (a) SBP model; (b) DBP model

Fig. 11. Correlation plots and Bland-Altman plots of dual-channel BP detection model based on SVR. (a)(c) SBP model; (b)(d) DBP model

Fig. 12. Changes of BP_{and K value. (a) Different times in one day; (b) exercise time}