A Wireless Power Transfer System for Cardiac Pacemakers Based on Flexible Dual‐Magnetic‐Negative Metamaterial Array

ABSTRACT To address the low power transfer efficiency (PTE) of wireless power transfer (WPT) systems for cardiac pacemakers and the limited conformability of conventional metamaterials to the curvature of the human body, this paper proposes a WPT system for cardiac pacemakers based on a flexible dual‐magnetic‐negative metamaterial array. First, the influence of the geometric parameters of the flexible magnetic‐negative metamaterial (MNG) units on the PTE of the WPT system is analyzed. The number of turns, trace width, and inter‐turn spacing are then optimized to maximize the PTE. Next, based on the negative refraction characteristics of the unit, a flexible dual‐magnetic‐negative metamaterial array composed of two types of negative‐permeability units is constructed. The improvement in the transmission performance of the WPT system, as well as its safety, is evaluated through simulations and experiments under bending angles ranging from 0° to 50°. Experimental results show that at a transmission distance of 20 mm, the integration of the flexible dual‐magnetic‐negative metamaterial array increases the PTE of the WPT system by at least 38.47%. When the receiving coil experiences lateral misalignment and angular deviation, the system maintains transmission efficiencies of 28.35% and 24.22%, respectively. During a 30‐min charging test, the maximum temperature rise in the surrounding tissue is 1.8°C, which complies with human safety standards.