27-GHz Silicon-Integrated Rectenna Based on Novel Multilayer Substrate

This paper presents the design, fabrication, and characterization of a multi-layer 27-GHz rectenna integrated entirely on silicon, aimed at achieving full CMOS compatibility for energy harvesting applications. The device is fabricated on a high-resistivity silicon (HRSi) substrate, which is selectively etched to create a low-permittivity region for the antenna while maintaining a high-permittivity full substrate for the rectifier circuit. The rectenna, operating in the millimeter-wave (mmWave) band, features a compact single-cell design with dimensions of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$13 \times 13 ~\text{mm}^{2}$</tex> only, making it suitable for integrating IoT devices to support energy autonomy. The rectenna utilizes a GaAs diode rectifier and achieves a measured maximum RF-to-DC power conversion efficiency (PCE) of about 49% at an input power of 12 dBm. This work demonstrates the potential of HRSi-based, silicon-integrated rectennas for efficient energy harvesting in IoT applications. The proposed multilayer fabrication technology allows the realization of high-radiation-efficiency directive antennas and RF circuits directly onto the CMOS substrate, without increasing the overall size of the circuit and maintaining the structural integrity of the device.