Efficient wireless power transfer via magnetic resonance coupling using automated impedance matching circuit

In this paper, an automated impedance matching circuit is proposed to match the impedance of the transmit and receive resonators for optimum wireless power transfer (WPT). This is achieved using a 2D open-circuited spiral antenna with magnetic resonance coupling in the low-frequency ISM band at 13.56 MHz. The proposed WPT can be adopted for a wide range of commercial applications, from electric vehicles to consumer electronics, such as tablets and smartphones. The results confirm a power transfer efficiency between the transmit and receive resonant circuits of 92%, with this efficiency being sensitive to the degree of coupling between the coupled pair of resonators

Enhancement algorithm for reverse loop technique on planar reverse loop antenna

Finding a trade-off balance between wireless transfer efficiency (WTE) and distance is a key issue in wireless energy transfer (WET). This paper presents a method of reducing the radical alteration in WTE versus distance, by using a reverse loop technique on planar reverse loop antenna (PRLA). The design focuses on 13.56 MHz Near Field Communication (NFC). The first stage uses mathematical modelling, based on an analytical approach, to determine the size of the reverse loop using Matlab. The proposed model predicts the size of the reverse loop to stabilize the WTE at a closer distance. Next, full-wave electromagnetic simulations are applied, using the computer simulation technology (CST) MICROWAVE STUDIO®, to determine the WTE effect with distance changes with mismatch condition. Planar loop antennas (PLAs) are fabricated on glass-reinforced epoxy laminated sheets (FR4). A validation of the simulation result in a real test scenario, using these PLAs and PRLA, confirms a stability enhancement in WTE at closer distance using the reverse loop technique, compared to conventional designs