Highly Efficient Asymmetric Power Division and System-Level Integration for Millimeter-Wave SWIPT: Theory, Design, and Experiment

Traditionally, simultaneous wireless information and power transfer (SWIPT) has employed equal power division between the communication and rectification paths. However, this symmetric approach is suboptimal, as the power requirements for information decoding and energy harvesting (EH) are inherently different, leading to energy inefficiencies. To overcome this limitation, we propose and experimentally validate an asymmetric power divider (PD) and system-integrated design for millimeter-wave (mmWave) SWIPT. The proposed system integrates an asymmetrically allocated PD, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$</tex-math> </inline-formula> circularly polarized (CP) receiving antenna array with a 36.1% impedance bandwidth, a 30.2% axial ratio bandwidth (ARBW), and a 19.6-dBic peak gain, together with a wideband, high-efficiency rectifier circuit. The measurement results demonstrate that the signal-to-noise ratio (SNR) of both the 28-GHz modulated signal and continuous wave (CW) signal at the communication port exceeds 56 dB. At the rectifier port, a maximum RF-to-dc conversion efficiency of 60.5% is achieved when the input power is 18 dBm. This work presents the first system-level experimental verification of an SWIPT system with asymmetric power division operating in the mmWave band. The proposed design offers several advantages, including an adjustable power ratio, broad bandwidth, high gain, high RF-to-dc conversion efficiency, and ease of integration. Therefore, it holds significant potential for future mmWave Internet of Things (IoT) applications and wireless energy, communication, and sensing networks.