Wireless Power Transfer Goes Farther with Metamaterials

 

Sergio Picozzi, Ph.D.
Associate Professor of Practice
Associate Director of the Masterials Science and Engineering Master's Program 
Department of Electrical Engineering and Computer Science
The Catholic Universitry of America 

Wed October 25, 2023 - 4:00 PM

Wireless Power Transfer (WPT) refers to processes in which Electromagnetic (EM) energy traverses a medium (air, generally) separating a source and a load without being confined by any guiding structures. WPT technologies can be classified into near-field and far-field. In the former, energy is stored within reactive EM fields surrounding the source, and a load placed within those fields can extract some of the fields’ energy once successful coupling is established. The coupling can be realized via either electric near fields (capacitive coupling) or magnetic near fields (inductive coupling). In far-field schemes, on the other hand, energy is conveyed by radiative EM fields, i.e., by EM waves. The waves are radiated by transmit antennas fed by the source and collected by receive antennas connected to the load. This presentation focuses on near-field solutions relying on inductive near field coupling. Inductive coupling (IC) near-field WPT architectures are based on the same working principles as ordinary transformers, involving magnetic-field coupling between a primary (transmit) circuit and a secondary (receive) circuit. Strategies to improve the Power Transfer Efficiency (PTE) include increasing the magnetic flux out of the transmit circuit, and enhancing the mutual inductance between transmit and receive circuit. The former objective can be achieved by using resonant circuits for the primary and secondary, tuned to resonate at the same frequency. The latter may be realized by augmenting the system with metamaterials. EM fields within or around metamaterials may assume configurations that differ in important ways from those attainable with ordinary materials. Metamaterials may be used, depending on their characteristics, either to steer magnetic flux more directly towards the receive circuit to strengthen the coupling, or to reflect magnetic flux directed away from the receive circuit in order to reduce flux leakage. Metamaterial-enhanced resonant inductive coupling designs present perhaps the most promising approach to near-field WPT systems.  We are carrying out a project comprising the design, construction, and testing of a wireless power transfer system based on this scheme. We will be presenting results of simulations assessing the impact of metamaterial structures upon the system’s performance. 

Refreshments served at 3:45 PM

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