[1]

Imura T and Hori Y (2011) Maximizing air gap and efficiency of magnetic resonant coupling for wireless power transfer using equivalent circuit and Neumann formula. IEEE Transactions on Industrial Electronics 58, 4746–4752.

[2]

Berger A, Agostinelli M, Vesti S, Oliver JA, Cobos JA and Huemer M (2015) Phase-shift and amplitude control for an active rectifier to maximize the efficiency and extracted power of a wireless power transfer system. Proceedings of IEEE-APEC, Charlotte, NC, USA, pp. 1620–1624.

[3]

Cove SR, Ordonez M, Shafiei N and Zhu J (2016) Improving wireless power transfer efficiency using hollow windings with track-width-ratio. IEEE Transactions on Power Electronics 31, 6524–6533.

doi: 10.1109/TPEL.2015.2498638
[4]

Zhu Q, Su M, Sun Y, Tang W and Hu AP (2018) Field orientation based on current amplitude and phase angle control for wireless power transfer. IEEE Transactions on Industrial Electronics 65, 4758–4770.

doi: 10.1109/TIE.2017.2767556
[5]

Zhang Y, Lu T, Zhao Z, He F, Chen K and Yuan L (2015) Quasi-uniform magnetic field generated by multiple transmitters of magnetically-coupled resonant wireless power transfer. Proceedings of IEEE-ICEMS, Pattaya, Thailand, pp. 1030–1034.

[6]

You Y, Soong BH, Ramachandran S and Liu W (2010) Palm size charging platform with uniform wireless power transfer. Proceedings of IEEE International Conference on Control Automation, Robotics & Vision, Singapore, Singapore, pp. 85–89.

[7]

Casanova JJ, Low ZN, Lin J and Tseng R (2009) Transmitting coil achieving uniform magnetic field distribution for planar wireless power transfer system. Proceedings of IEEE Radio and Wireless Symposium, San Diego, CA, USA, pp. 530–533.

[8]

Wireless Power Consortium (2017) The qi Wireless Power transfer system power class 0 specification, v1.2.3, Parts 1 and 2: interface definitions.

[9]

Galizzi M, Caldara M, Re V and Vitali A (2013) A novel qi-standard compliant full-bridge wireless power charger for low power devices. Proceedings of IEEE WPT, Perugia, Italy, pp. 44–47.

[10]

Waffenschmidt E (2011) Wireless power for mobile devices. Proceedings of IEEE INTELEC, Amsterdam, Netherlands, pp. 1–9.

[11]

Abouzeid MO and Tekin A (2017) Adaptive 6.78-MHz ISM band wireless charging for small form factor receivers. Proceedings of IEEE ISCAS, Baltimore, MD, USA, pp. 1–4.

[12]

Park Y-J, Jang B, Park S-M, Ryu H-C, Oh SJ, Kim S-Y, Pu Y, Yoo S-S, Hwang KC, Yang Y, Lee M and Lee K-Y (2018) A triple-mode wireless power-receiving unit with 85.5% system efficiency for a4wp, wpc, and pma applications. IEEE Transactions on Power Electronics 33, 3141–3156.

doi: 10.1109/TPEL.2017.2703153
[13]

Johns B, Antonacci T and Siddabattula K (2012) Designing a qi-compliant receiver coil for wireless power systems, part1, TI. [Online] Available at https://www.mouser.com/pdfDocs/TI-Designing-aQi-compliant-receiver-coil.pdf.

[14]

Chen MX and Cheng KWE (2017) Design of flat magnetic core for inductively coupled coils in high efficiency wireless power transfer application. Proceedings of International Conference PESA-Smart Mobility, Power Transfer & Security, Hong Kong, China, pp. 1–7.

[15]

Campi T and Feliziani SCM (2014) Magnetic shielding of wireless power transfer systems. Proceedings of International Symposium EMC, Tokyo, Japan, pp. 422–425.

[16]

Ahn D, Kim S, Kim S-W, Moon J and Cho I (2017) Wireless power transmitter and receiver supporting 200-kHz and 6.78-MHz dual-band operation without magnetic field canceling. IEEE Transactions on Power Electronics 32, 7068–7082.

doi: 10.1109/TPEL.2016.2629494
[17]

Zhao C and Costinett D (2017) Gan based dual-mode wireless power transfer using multifrequency programmed pulse width modulation. IEEE Transactions on Industrial Electronics 64, 9165–9176.

doi: 10.1109/TIE.2017.2681974
[18]

Riehl PS, Satyamoorthy A, Akram H, Yen Y-C, Yang J-C, Juan B, Lee C-M, Lin F-C, Muratov V, Plumb W and Tustin PF (2015) Wireless power systems for mobile devices supporting inductive and resonant operating modes. IEEE Transactions on Microwave Theory and Techniques 63, 780–790.

doi: 10.1109/TMTT.2015.2398413
[19]

Rooij M and Zhang Y (2016) A 10 W multi-mode capable wireless power amplifier for mobile devices. Proceedings of IEEE PCIM, Shangai, China, China, pp. 1–8.

[20]

Burket C (2017) Wireless charging opportunities and challenges for wearables: one size does not fit all. IEEE Power Electronics Magazine 4, 53–57. .

[21]

Roshan YM and Park EJ (2017) Design approach for a wireless power transfer system for wristband wearable devices. IET Power Electronics 10, 931–937.

doi: 10.1049/iet-pel.2016.0616
[22]

Cannon BL, Hoburg JF, Stancil DD and Goldstein SC (2009) Magnetic resonant coupling as a potential means for wirelesspower transfer to multiple small receivers. IEEE Transactionson Power Electronics 24, 1819–1825.

doi: 10.1109/TPEL.2009.2017195
[23]

Li X, Zhang H, Peng F, Li Y, Yang T, Wang B and Fang D (2012) A wireless magnetic resonance energy transfer system for microimplantable medical sensors. Sensors 12, 10292–10308.

doi: 10.3390/s120810292
[24]

Ezzulddin AS and Ibraheem AA (2017) Design and optimization of printed spiral coils used in wireless power transmission systems for powering 10 mm2 receiver size at 13.56 MHz operating frequency. International Journal of Current Engineering and Technology 7, 1835–1841.

[25]

Jow U and Ghovanloo M (2009) Modeling and optimization of printed spiral coils in air, saline, and muscle tissue environments. IEEE transactions on Biomedical Circuits and Systems 3, 339–347.

doi: 10.1109/TBCAS.2009.2025366
[26]

Ko WH, Liang SP and Fung CDF (1977) Design of radio frequency coils for implant instruments. Medical & Biological Engineering & Computing Journal, 634–640.