Study on 920MHz band FSK demodulation circuit using SAW filters for SWIPT realization

In recent years, Radio Frequency Wireless Power Transfer (RF-WPT) has garnered significant attention as a promising method for powering small Internet of Things (IoT) devices. One of the key advantages of RF-WPT is its ability to simultaneously transfer both power and information (Simultaneous Wireless Information and Power Transfer: SWIPT). However, previous SWIPT studies on RF-WPT have been largely theoretical and require further research from practical perspectives. In this paper, we focus on the practical realization of SWIPT using RF-WPT. To avoid any loss of power transmission efficiency, we present a circuit that extracts power and ASK signals from 2-FSK using a Surface Acoustic Wave (SAW) filter. This circuit has been designed to be small in size.