Highly efficient, broadband, hexagonal shaped rectenna for energy harvesting in IoT applications

This study shows an efficient broadband rectenna for energy harvesting in Internet of Things (IoT) applications. It covers the 3.6–6.45 GHz band, which includes the mid-5G band (3.6-3.8 GHz), the Wi-Fi 5 GHz band (5.150–5.850 GHz), and the lower 6 GHz (5.925–6.425 GHz) Wi-Fi 6E band. To make the system more cost-effective, the rectenna is made up of a broadband antenna, an Impedance Matching Network (IMN), and a rectifier circuit built on the Flame Retardant (FR4) substrate with a compact optimized area of $30\times 30{\mathrm{mm}}^2$. Proper impedance matching and bandwidth are provided via a Coplanar Waveguide (CPW) fed hexagonal patch, tuning stubs, and a slot on the partial ground. With enhanced radiation efficiency, the suggested antenna displays an omnidirectional radiation pattern. A Schottky diode (Infineon BAT15-03 W) based rectifier circuit is then used to rectify the received electromagnetic signal. The impedance-matching network connects the circuit to the antenna. By using transmission lines for broadband frequency operation, the suggested Impedance Matching Network (IMN) lowers the complexity of the rectenna. With a 1 K$\Omega$ load resistance, it exhibits a continuous efficiency above 40% and output voltage above 1.3 V throughout the frequency range 3.6-6.45 GHz, with the highest recorded Power Conversion Efficiency (PCE) of 59.82% and output voltage of 1.9 V at 5.8 GHz at input power 9 dBm. The results confirm that the recommended rectenna is suitable for low-power applications throughout a wide frequency range.