The principles of electromagnetic induction are applied in many devices and systems, including induction cookers, transformers and wireless energy transfer; however, few data are available on resonance in the electromotive force (EMF) of electromagnetic induction. We studied electromagnetic induction between two circular coils of wire: one is the source coil and the other is the pickup (or induction) coil. The measured EMF versus frequency graphs reveals the existence of a resonance/anti-resonance in the EMF of electromagnetic induction through free space. We found that it is possible to control the system’s resonance and anti-resonance frequencies. In some devices, a desired resonance or antiresonance frequency is achieved by varying the size of the resonator. Here, by contrast, our experimental results show that the system’s resonance and anti-resonance frequencies can be adjusted by varying the distance between the two coils or the number of turns of the induction coil.
 A. Kurs, A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher and M. Soljacic, “Wireless Power Transfer via Strongly Coupled Magnetic Resonances,” Science, Vol. 317, No. 5834, 2007, pp. 83-86. doi:10.1126/science.1143254
 T. Imura, T. Uchida and Y. Hori, “Flexibility of Contactless Power Transfer using Magnetic Resonance Coupling to Air Gap and Misalignment for EV,” World Electric Vehicle Journal, Vol. 3, 2009, pp. 1-10.
 S. A. Hackworth, X. Liu, C. Li and M. Sun, “Wireless Solar Energy to Homes: A Magnetic Resonance Approach,” International Journal of Innovations in Energy Systems and Power, Vol. 5, No. 1, 2010, pp. 40-44.
 B. Wang, T. Nishino and K. H. Teo, “Wireless Power Transmission Efficiency Enhancement with Metamaterials,” Proceedings of Wireless Information Technology and Systems of 2010 IEEE International Conference, Honolulu, 28 August-3 September 2010, pp. 1-4. doi:10.1109/ICWITS.2010.5612284
 V. M. Dubovik, M. A. Martsenyuk and B. Saha, “Material Equations for Electromagnetism with Toroidal Polarizations,” Physics Review E, Vol. 61, No. 6, 2000, pp. 7087-7097. doi:10.1103/PhysRevE.61.7087
 G. N. Afanasiev, “Simplest Sources of Electromagnetic Fields as a Tool for Testing the Reciprocity-Like Theorems,” Journal of Physics D: Applied Physics, Vol. 34, No. 4, 2001, pp. 539-559. doi:10.1088/0022-3727/34/4/316
 H. Schmid, “Toroidal Moments in Spin-Ordered Crystals,” Proceedings of One Day International Research Workshop on Super-Toroidal Electrodynamics, University of Southampton, Southampton, 2004, pp. 108-177.