TY - JOUR
T1 - Analysis of antenna structure for energy beamforming in wireless power transfer
AU - Lim, Yongseok
AU - Ahn, Hyun Seok
AU - Park, Jongsun
N1 - Funding Information:
Manuscript received September 30, 2016; revised June 16, 2017; accepted September 3, 2017. Date of publication September 19, 2017; date of current version October 27, 2017. This work was supported in part by the Korea Government (MSIP) through the National Research Foundation under Grant 2016R1A2B4015329 and in part by the Korea Government (MSIT) through IT Research and Development Program of IITP under Grant R-20160222-002757. (Corresponding author: Jongsun Park.) The authors are with the School of Electrical Engineering, Korea University, Seoul 136-701, South Korea (e-mail: busytom.korea@gmail.com; jongsun@ korea.ac.kr).
Publisher Copyright:
© 1963-2012 IEEE.
PY - 2017/11
Y1 - 2017/11
N2 - The technology to send a magnetic field in a particular direction, known as energy beamforming, has been recently introduced as a magnetic field shaping technology in nonradiative wireless power transmission. In general, one of the most efficient conditions for energy beamforming is that the magnetic fields induced by each antenna should be synthesized to head the same direction. To synthesize the magnetic fields induced at each antenna, interference by mutual inductance that can occur between transmitting (TX) antennas should be minimized. In addition, energy should not be exchanged between the TXs, otherwise it lowers the transmission efficiencies of TX and receiving antenna. In this paper, we present an optimal antenna structure that minimizes the mutual inductance between two TX antennas. First, we have analyzed the mutual inductance between TX antennas that have asymmetric sizes with different antenna lengths and arrangement angles. The directivity of the magnetic field vector is also investigated through an experimental analysis of an antenna structure. Finally, it has been verified that the optimal TX antennas for energy beamforming should be symmetric, which means that all the length of antennas are same and disposed perpendicular to each other. The experimental results show that the deviations of magnetic field directivity for symmetric and asymmetric antennas are 0.045 and 0.355, respectively, which shows that the symmetric structure shows 8.2 times larger consistency over the asymmetric structure.
AB - The technology to send a magnetic field in a particular direction, known as energy beamforming, has been recently introduced as a magnetic field shaping technology in nonradiative wireless power transmission. In general, one of the most efficient conditions for energy beamforming is that the magnetic fields induced by each antenna should be synthesized to head the same direction. To synthesize the magnetic fields induced at each antenna, interference by mutual inductance that can occur between transmitting (TX) antennas should be minimized. In addition, energy should not be exchanged between the TXs, otherwise it lowers the transmission efficiencies of TX and receiving antenna. In this paper, we present an optimal antenna structure that minimizes the mutual inductance between two TX antennas. First, we have analyzed the mutual inductance between TX antennas that have asymmetric sizes with different antenna lengths and arrangement angles. The directivity of the magnetic field vector is also investigated through an experimental analysis of an antenna structure. Finally, it has been verified that the optimal TX antennas for energy beamforming should be symmetric, which means that all the length of antennas are same and disposed perpendicular to each other. The experimental results show that the deviations of magnetic field directivity for symmetric and asymmetric antennas are 0.045 and 0.355, respectively, which shows that the symmetric structure shows 8.2 times larger consistency over the asymmetric structure.
KW - Beamforming antenna
KW - energy beamforming
KW - magnetic field shaping
KW - wireless power antenna
KW - wireless power transfer (WPT)
UR - http://www.scopus.com/inward/record.url?scp=85030766965&partnerID=8YFLogxK
U2 - 10.1109/TAP.2017.2754326
DO - 10.1109/TAP.2017.2754326
M3 - Article
AN - SCOPUS:85030766965
SN - 0018-926X
VL - 65
SP - 6085
EP - 6094
JO - IEEE Transactions on Antennas and Propagation
JF - IEEE Transactions on Antennas and Propagation
IS - 11
M1 - 8046032
ER -