Development of patch-type sensor module for battery-free power transfer and data transmission

This paper presents power and data transmission technology that can be used in patch-type module for epidermal electronics of wearable devices. Proposed technology based on passive RFID is a system that can transmit a data and power between patch-type module without battery and wearable devices, such as a smart watch. To improve the read distance and power transmission efficiency, the passive RFID system used a new matching circuit instead of impedance matching method. The maximum read distance was increased to 12.5 cm, which was 56% increase comparing the existing impedance matching method. This research showed the feasibility of power and data transmission between patch-type module and smart watch.