Simultaneous wireless information and power transmission system based on a dual-frequency metasurface design

Nowadays, the number of wireless sensor devices is increasing rapidly, posing persistent challenges related to battery replacement and power wiring. This paper presents a simultaneous wireless information and power transmission (SWIPT) scheme based on a frequency diversity metasurface design, which provides a wireless power supply scheme for electrical devices such as sensors. The metasurface is designed with frequency bands commonly found in the environment, and achieves efficient absorption of electromagnetic (EM) energy at 5.8 GHz and radiation of sensor information at 2.45 GHz, making it possible to take full advantage of the energy in the environment and easy to integrate with existing systems. The branches for the dual-square loop are designed based on spatial impedance matching and equivalent circuit, giving the metasurface advantages such as compact layout (unit size of 0.16λ0×0.16λ0×0.012λ0, where λ0 is the wavelength at 2.45 GHz), high isolation (S21< −20 dB within the operating frequency band), and insensitivity to incident angles (efficiency over 80% within 60°). Integrated with rectification circuits and sensors, it efficiently converts EM waves received by the metasurface into direct current (DC) power for sensor operation. The sensors then radiate information through the metasurface, effectively addressing challenges related to sensor device wiring and battery replacement, thereby offering new solutions for the development of next-generation smart cities.