Flexible Multi-Channel Heterogeneous Integrated Low Form Factor Wireless Multi-Channel Surface Electromyography (Semg) Device

We demonstrate a new approach of making flexible surface electromyography (sEMG) system on our flexible platform called “FlexTrateTM” that is based on die-first flexible Fan-Out Wafer-Level Packaging (FOWLP) technique. FlexTrateTM allows solderless heterogeneous integration of bare dielets at 20-40 µm pad pitches not achievable using conventional PCB technology. The integration of small bare dielets reduces the overall form factor and improves flexibility of the device. In this work, we demonstrate up to 12 bipolar configuration sEMG channels on FlexTrateTM. We call this system FlexsEMG. Increasing the number of channels helps to provide increased spatial resolution that enables more sophisticated analysis of the muscles such as evaluation of the muscle fiber conduction velocity (MFCV) which is a biomarker for many physiological and muscular conditions. To the best of our knowledge, this is the first demonstration of up to 12 bipolar sEMG channels on the thinnest and fully flexible platform. Overall, the FlexsEMG system is 74 mm x 25 mm x 1 mm in size and integrates a Bluetooth low energy (BLE) chip, an efficient front-end data processing dielet, passives, and twenty gold-capped vertically corrugated flexible dry copper electrodes. We power the system through a rechargeable battery and use an adhesive to attach the device in place on the skin. The FlexsEMG system is mechanically robust, foldable, thin (1 mm), and lightweight (< 5 g). We evaluate root mean square (RMS), mean frequency (MNF), and MFCV of the bicep muscle using this device. The ability to acquire these signals through our device in a mobile setting is critical for the study of many muscular physiological phenomena, disorders, and general physiological monitoring.