Design of self-diplexing rectenna enabling simultaneous wireless power transfer and bio-telemetry for on-body applications

• A small self-diplexing rectenna is made for bio-telemetry and Wireless Power Transfer (WPT) at the same time. • Using a bent resonator with an L-shaped stub, the device can work on two bands: 5 GHz (WPT) and 5.65 GHz (telemetry). • The antenna has a good inter-band isolation of < –27 dB and is built on a FR4 substrate that is 1.6 mm thick. • A 5 GHz voltage-doubler rectifier with lumped matching gets 81.5% RF–DC PCE at 0 dBm and keeps >40% PCE from –30 to 10 dBm with –50 dBm sensitivity. • Frequency- and power-weighted efficiencies reach 96% • The integrated rectenna has a 24.2% PCE at 10 dBm with a 1 kΩ load. • When tested on the body, a silicon-encapsulated rectenna had low 10-g SAR values of 0.0574 W/kg (5 GHz) and 0.067 W/kg (5.65 GHz). • Prototypes of antennas and rectifiers confirm that they are small, simple, and good for real-world WPT uses. This study presents the design of a self-diplexing rectenna for simultaneous Wireless Power Transfer and bio telemetry applications. The antenna, configured on a 1.6 mm-thick FR4 substrate, operates at two distinct frequencies: 5 GHz and 5.65 GHz. The lower band is allocated for wireless power transfer, whereas the upper band supports data telemetry. A curved resonator, aligned with an L-shaped stub, generates these dual resonances while maintaining a high isolation of ≤ − 27 dB between the two frequency bands. A rectifier, which is a voltage doubler circuit, is designed to operate at 5 GHz. A lumped element matching network is employed at the input of the rectifier. The RF-to-DC Power Conversion Efficiency (PCE) of the rectifier is measured to be 81.5% at an input power of 0 dBm and it also maintains a PCE >40% for a wide input range of -30 to 10 dBm and offers a high sensitivity of -50dBm. The frequency weighted and the power weighted efficiencies are found to 96. The proposed antenna and the rectifier are integrated to form a rectenna. For a given input power of 10 dBm and a load impedance of 1 KΩ, the measured PCE is 24.2%. The rectenna encapsulated in a silicon case is simulated near a human arm model, revealing peak 10-g SAR values of 0.0574 W/kg at 5 GHz and 0.067 W/Kg at 5.65 GHz. The prototypes of the antenna and the rectifier are fabricated and then integrated to form a rectenna for testing purposes. The antenna’s compact size, simple structure, and dual-band operation make it an attractive solution for emerging wireless power transfer applications.