Flexible Receiver Antenna Prepared Based on Conformal Printing and Its Wearable System

Area of Science:

• Electrical Engineering
• Materials Science
• Biomedical Engineering

Background:

• Microwave energy offers stable wireless power transfer for wearables.
• Conventional radio frequency (RF) energy harvesters use rigid antennas, limiting wearability.
• Flexible and conformal antennas are needed for comfortable and effective wearable energy harvesting.

Purpose of the Study:

• To develop a wearable RF energy harvesting system with a flexible dual-band antenna.
• To improve wearability by minimizing performance loss due to bending.
• To enhance energy conversion efficiency for continuous power supply.

Main Methods:

• Fabrication of a flexible dual-band antenna (915 MHz/2.45 GHz) using conformal 3D printing on curved surfaces.
• Integration of a hybrid microstrip-lumped element rectifier circuit.
• Testing the system with commercial 915 MHz transmitters and Wi-Fi routers.

Main Results:

• The flexible antenna minimized performance loss on arm-mimicking curvatures.
• The hybrid rectifier achieved enhanced energy conversion efficiency.
• The system consistently delivered 3.27-3.31 V, enabling continuous power for physiological monitoring and data transmission.

Conclusions:

• This work presents a practical solution for sustainable energy harvesting in flexible wearables.
• The conformal 3D-printed antenna and efficient rectifier circuit overcome limitations of conventional rigid designs.
• The developed system supports continuous operation of wearable devices for real-time monitoring and data transmission.