Using self-resonant coils in a strongly coupled regime, we experimentally demonstrated efficient nonradiative power transfer over distances up to 8 times the radius of the coils. We were able to ...transfer 60 watts with ∼40% efficiency over distances in excess of 2 meters. We present a quantitative model describing the power transfer, which matches the experimental results to within 5%. We discuss the practical applicability of this system and suggest directions for further study.
We present numerical experiments showing how coupled-mode theory can be systematically applied to join very dissimilar photonic crystal waveguides with 100% transmission. Our approach relies on ...appropriately tuning the coupling of the evanescent tail of a cavity mode to each waveguide. The transition region between the waveguides may be as short as a few lattice spacings. Moreover, this technique only requires varying a small number of parameters (two for each waveguide in our example) and the tuning to each waveguide may be done separately, greatly simplifying the computations involved.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.
Includes bibliographical references (leaves 41-42).
Using self-resonant coils in a strongly coupled regime, we ...experimentally demonstrate efficient non-radiative power transfer over distances of up to eight times the radius of the coils. We use this system to transfer 60W with approximately 45% efficiency over distances in excess of two meters. We present a quantitative model describing the power transfer which matches the experimental results to within 5%, and perform a finite element analysis of the objects used. We finally discuss the robustness of the mechanism proposed and consider safety and interference concerns.
by André Kurs.
S.M.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 99-105).
We first demonstrate ...theoretically and experimentally that electromagnetic resonators with high quality factors (Q) can be used to transfer power efficiently over distances substantially larger than the characteristic dimensions of the resonators by operating in a so-called "strongly coupled" regime. We next generalize the notion of strongly coupled resonances to a system comprising one power source and multiple receivers in a regime of broad practical applicability and show that, by appropriately tuning the parameters of the system, it is possible to significantly improve the overall efficiency of the wireless power transfer relative to the single-source and single-receiver configuration. We experimentally verify the predicted improvement in efficiency for a system consisting of one large source (area ~ 1 m2 ) coupling to two much smaller receivers of dimensions comparable to those of many portable electronic devices (area ~ 0.07 m2 ). Next, we present a novel design for an electrical conductor whose structure is optimized to have the lowest achievable resistance in the 2-20 MHz frequency range, where it can offer performance an order of magnitude better than the best currently available conductors. The two following chapters deal with energy transport in photonic crystals. We first investigate numerically how a square lattice of dielectric rods may be used to collimate a laser beam and the feasibility of using this system as a chemical sensor. Finally, we present and demonstrate through specific examples a systematic and general procedure, which is both computationally inexpensive and straightforward to implement, for coupling strongly dissimilar waveguides with 100% transmission.
by André B. Kurs.
Ph.D.
PDF
