Synthetic high-order non-Hermitian bound state in the continuum for enhanced wireless power transfer

Magnetic resonance wireless power transfer (WPT) with parity−time- (PT-)symmetry has been extensively studied due to its high transfer efficiency. However, conventional second-order PT-symmetric systems face several challenges in practical WPT applications. Due to near-field coupling, frequency splitting occurs in the strong coupling region, necessitating frequency tracking to maintain optimal transfer efficiency. Although the system can operate at a fixed frequency in the weak coupling region, the efficiency is significantly reduced. Strict PT-symmetry constraints also limit the system’s flexibility in engineering applications. Additionally, severe field leakage from the transmitter coil in the strong coupling region leads to poor electromagnetic compatibility. Here, we demonstrate efficient WPT by implementing a bound state in the continuum (BIC) in a high-order non-Hermitian system based on a composite transmitter. BICs offer greater flexibility in practical applications as they do not require strict PT-symmetry. Remarkably, the optimized WPT system constructed with a composite transmitter maintains a stable pure real working frequency, reduces field leakage from the transmitter coil, and exhibits significant advantages over conventional second-order PT-symmetric systems. Our finding expands the application of BICs in high-efficiency WPT systems and provides a robust platform for realizing miniaturized and integrated high-order non-Hermitian WPT systems.