Design Methodology of Near-Field Transmitter Coil
Antenna for Maximizing Efficiency of the WPT
System
Ananth Bharadwaj∗ , Vivek Kumar Srivastava† , Chakradhar C. Reddy‡ Ashwani Sharma§ ,
∗ Indian
Institute of Technology Ropar, Rupnagar, India, 2018eez0023@iitrpr.ac.in*
Institute of Technology Ropar, Rupnagar, India, vivek.19eez0027@iitrpr.ac.in*
§ Indian Institute of Technology Ropar, Rupnagar, India, reddy@iitrpr.ac.in*
‡ Indian Institute of Technology Ropar, Rupnagar, India, ashwani.sharma@iitrpr.ac.in*
† Indian
Abstract—This article provides a comprehensive stepwise procedure to develop a transmitter (Tx) coil antenna for a near-field
WPT system. The design procedure enables to determine the
parameters such as distance between Tx and Receiver (Rx) coils
(h), side-length (2a), the number of turns (Nt ), and resonant
frequency (fc ) of Tx coil. These parameters are optimized based
on the application scenario, maximum magnetic field strength
(H), safety guidelines, and quality factor (Q). Further, the
analytical H-field results are verified by the EM simulator.
Moreover, by choosing an appropriate load resistance (RL ) and
optimal circuit parameters, the link efficiency (η) between TxRx coils and system efficiency (ηdc−dc ) are maximized using the
LT-Spice circuit simulator.
Index Terms—Tx coil antenna, wireless power transfer (WPT),
magnetic resonance coupling (MRC), drone, Q-factor, link efficiency, system efficiency.
I. I NTODUCTION
The exploitation of near-field Wireless Power Transfer
(WPT) is exponentially increasing in many major application areas, such as electric vehicles (EVs) [1], drones [2],
mobile devices [3], and biomedical implants [4]. A massive
breakthrough by MIT researchers in the Magnetic Resonance
Coupling (MRC) technique led to this increase in demand and
made the WPT system practically viable. Broadly, the WPT
system consists of a transmitter (Tx) coil, receiver (Rx) coil,
and compensation capacitors. Here, the Rx coil parameters are
generally based on the application scenario. However, the Tx
coil antenna is the utmost significant component of the WPT
system in enhancing the link efficiency (η).
Previously in [5]–[7], many researchers have developed
various methodologies to design a Tx coil antenna. In [5],
[6], the Tx coil is solely optimized based on the quality (Q)
factor. Here, the optimization algorithm includes Tx coil turns
(Nt ), spacing between the turns and conductive track width.
However, the maximum dimension of the Tx coil in [5] is
selected based on design limitation, which significantly differs
based on the testing facility. Further, the choice of resonant
frequency (fc ) is not included in the optimization process.
At the same time, in [7], the optimization design procedure
of the Tx coil antenna is based on skin effect, proximity
effect, and current crowding of the wire at fc = 6.78 MHz.
Nevertheless, high-frequency Litz wires reduce the parasitic
Drone
Receiver Coil
Transmitter Coil
Fig. 1. Scenario of wireless drone charging system.
effects, which may not require any sophisticated algorithm.
Moreover, in [7], the proposed design procedure lacks the
selection of coil parameters and fc , which are the most critical
design parameters. On the contrary, the optimization procedure
in [8] of the Tx coil antenna includes a variation of fc based
on the maximization of the Q-factor. However, the design
procedure in [8] does not incorporate a variation of other
critical Tx coil parameters.
From the above literary works, it is evident that guidelines
to define a systematic design procedure for selecting Tx coil
antenna parameters, such as maximum side-length (2a) and
the number of turns (Nt ) are unexplored. Moreover, along
with Tx coil antenna parameters, the transfer distance (h)
between Tx-Rx coils and operational frequency (fc ) of the
WPT system was not jointly optimized in the works mentioned
above. Therefore, the authors were motivated to propose a new
design methodology that helps the researchers to select the Tx
coil antenna and system parameters. Moreover, the analysis
and simulation are performed based on the electric drone to
test the proposed design procedure, as shown in Fig. 1.
Section II presents the proposed design steps of Tx coil
antenna parameters. Whereas, Section III includes validation
of analytical results using the proposed design step with an EM
simulator. Further, the link efficiency and system efficiency are
determined using the LT-Spice simulator. Finally, the paper is
concluded in section IV.
This
paper's
copyright
is held
by the
author(s).
It is published
in theseonproceedings
and atincluded
in any
suchRestrictions
as IEEE Xplore
Authorized
licensed
use limited
to: Indian
Institute
of Technology
(Ropar). Downloaded
September 12,2023
16:01:47 UTC
fromarchive
IEEE Xplore.
apply.
under the license granted by the "Agreement Granting EurAAP Rights Related to Publication of Scholarly Work."
The design procedure of Tx coil antenna parameters is
sequentially outlined as follows:
B. Selection of maximum side-length 2a
The maximum side length, 2a, is optimized by achieving
the peak value of magnetic field (H-field) at the given h (for
instance, here 50 mm). Thereby, to maximize the H-field at
h = 50 mm, the analytical H-field equation for a single-turn
square coil carrying current IT is given as
4 (−1)i Pi
Qi
IT X
−
,
i+1
4π i=1 ri [ri + (−1)
Qi ]
ri [ri + Pi ]
r3 =
q
q
Q21 + P12 + h2 ,
r2 =
Q23 + P32 + h2 ,
r4 =
Q1 = −Q4 = a + x,
P1 = P2 = a + y,
q
q
(1)
Q22 + P22 + h2 ,
Q24 + P42 + h2 ,
Q2 = −Q3 = a − x,
P3 = P4 = −a + y.
Where, the parameters r1 , r2 , r3 and r4 are distances from the
corners of the square loop to the observation point O(x, y, h).
The maximum H-field at O(0, 0, h) is obtained by differentiating (1) with respect to a as
16a(−a5 + (ah)2 + h4 )
∂H
= 0.
=
3
∂a
(2a2 + h2 ) 2 (a2 + h2 )2
(2)
Solving the fifth order equation provided in (2), the five roots
of a are evaluated as
a1 = 0,
a3 =
a5 = −
a2 =
(1 +
√
2
(1 +
5)h
√
2
1
2
5)h
2
, a4 = −
1
2
2
-50
0
50
x(mm)
100
(a)
(1 −
√
(1 −
5)h2
2
√
2
5)h
1
2
,
1
2
2
,
(3)
2
.
Here, a1 , a2 , a3 , a4 , and a5 denote five roots of (2). Among all
the roots, only a3 is valid as all others are either zero, negative,
or imaginary, which cannot be physical dimensional values.
Further, by substituting h = 50 mm in a3 of (3), the value is
calculated as a = a3 = 63.6 mm. Thereby, the maximum side
length is obtained as 2a = 127.2 mm. Further, the graphical
Fig. 2. (a) Parametric variation of 2a with H, (b) 3D H-field distribution for
optimal 2a.
25
h=50 mm, 2a=127.2 mm
20
H(A/m)
The h between Tx-Rx coils is broadly selected based on the
application scenario. Wherein for the biomedical implants (low
power applications) h ranges in [10, 30] mm [9]–[11]. Whereas
for mobile and portable devices (medium power applications),
the transfer distance is generally fixed at h = 50 mm [3],
[6]. Similarly, the transfer distance in drones (medium power
applications) is normally rooted at h = 50 mm [12], [13].
Additionally, the transfer distance for electric vehicles (high
power applications) ranges in [100, 200] mm [14]–[16]. The
authors have selected a drone as an application scenario to
illustrate the design process. Thereby, the transfer distance is
selected as h = 50 mm.
r1 =
2a=060.0 mm
2a=080.0 mm
2a=100.0 mm
2a=127.2 mm
2a=140.0 mm
2a=160.0 mm
h=50 mm
3
1
-100
A. Selection of transfer distance h
H=
4
H(A/m)
II. P ROPOSED D ESIGN P ROCEDURE FOR S ELECTING T X
C OIL A NTENNA PARAMETERS
N t =1
15
N t =2
10
N t =4
N t =3
N t =5
5
N t =6
ICNIRP Limit
0
-100
-50
0
x(mm)
50
100
Fig. 3. Parametric variation of Nt with H.
representation of parametric variation of 2a with H is shown
in Fig. 2(a). Thereby, observing the Fig. 2(a) the peak value
of the H at (x = 0, y = 0, h = 50 mm) is maximized at
2a = 127.2 mm, which ensures the correctness of analytical
findings provided in (2) and (3). Moreover, the 3D H-field
distribution of a single Tx coil turn with 2a = 127.2 mm is
depicted in Fig. 2(b).
C. Selection of number of turns Nt
The number of turns Nt of square Tx coil antenna is optimized subject to ICNIRP guidelines (21 A/m or 27 µT) [17].
The value of Nt is incremented until the peak value of the
H-field reaches the ICNIRP limit of 21 A/m. The parametric
variation of Nt with H-field is displayed in Fig. 3. It is evident
from Fig. 3, that the peak value of H-field maximizes at
Nt = 5. Further increase in Nt will overshoot the ICNIRP
limit, as shown in Fig. 3.
D. Selection of operating frequency fc
The operating frequency (fc ) is selected by maximizing the
Q-factor using the EM simulator. The Q-factor of the Tx coil is
c LT
. Here, RT and LT are the resistance and
given as QT = ωR
T
inductance of the Tx coil and ωc = 2πfc denotes the operating
angular frequency of the WPT system. Fig. 4 represents the
variation of fc ranging in [1, 20] MHz with Rt , Lt , and Qt .
Here, the fc is selected based on the maximum Q-factor using
the data depicted in Fig. 4(c). The value of Rt increases at
higher values of fc due to skin and proximity effects, as shown
in Fig. 4(a). Similarly the value of Lt increases with fc as
depicted in Fig. 4(b). The Qt as defined above is proportional
to Lt , and inversely proportional to Rt . Therefore, the Lt
being dominant over Rt at lower values of fc , the Qt initially
increases as seen from Fig. 4(c). However, after reaching the
maximum Qt at optimal fc , the values of Rt influences over
Lt which results in reduction of Qt as shown in Fig. 4(c).
Moreover, the Qt values are plotted for distinct conductive
tracks w. It is observed from Fig. 4(a) that increase in w
This
paper's
copyright
is held
by the
author(s).
It is published
in theseonproceedings
and atincluded
in any
suchRestrictions
as IEEE Xplore
Authorized
licensed
use limited
to: Indian
Institute
of Technology
(Ropar). Downloaded
September 12,2023
16:01:47 UTC
fromarchive
IEEE Xplore.
apply.
under the license granted by the "Agreement Granting EurAAP Rights Related to Publication of Scholarly Work."
20
30
30
5
L t (uH)
Rt ( )
w=0.5 mm
w=1.0 mm
w=1.5 mm
w=2.0mm
10
h=50 mm, 2a=127.2 mm, N t =5
25
Vout (in volts)
h=50 mm, 2a=127.2 mm, N t =5
15
w=0.5 mm
w=1.0 mm
w=1.5 mm
w=2.0 mm
20
15
10
5
0
1
3
5
7
9
11
fc (MHz)
13
15
17
1
1920
3
5
7
9
11
13
15
17
1920
Nr=1
20
2b=100 mm
2b=104 mm
2b=108 mm
2b=112 mm
2b=116 mm
2b=120 mm
10
0
-100
-50
(a)
0
50
100
x(mm)
fc(MHz)
(a)
(b)
1000
h=50 mm, 2a=127.2 mm, N t =5
Fig. 6. (a) Vout variation with parametric sweep of 2b, (b) 3D Vout
distribution corresponding to optimal 2b.
Qt
750
500
w=0.5 mm
w=1.0 mm
w=1.5mm
w=2.0mm
250
Z
0
1
3
5
7
9
11 13 15 17 1920
fc(MHz)
(c)
Nr
X
Fig. 4. (a) Variation of Rt with fc for different conductive track width
(w), (b) variation of Lt with fc for different conductive track width (w), (c)
variation of Qt with fc for different conductive track width (w).
Nt
h
Y
Start
Transfer distance‘h’ is selected
based on application scenario.
Fig. 7. Layout of Tx-Rx coils resulted from proposed design procedure.
The maximum side-length ‘2a’ is selected based
on maximum H-field derived using (2) and (3).
20
Nt= Nt +1
Is H-field is
within ICNIRP
limits ?
H(A/m)
15
Initialize the Nt=1
10
5
Analytical H-field
Simulated H-field
Yes
0
-150
-100
-50
0
x(mm)
50
100
150
No
The optimal Tx turns is designated as Nt=Nt-1.
Fig. 8. Simulated H-field (H).
The optimal operating frequency (fc) is selected
based on optimal Q-factor of the Tx coil.
Stop
Fig. 5. Flow chart of Tx coil antenna design procedure.
result in reduction of Rt which augments the value of Qt .
Hence, it is always preferred to use large w to operate at high
Qt . The optimal fc point ranges between [12, 15] MHz from
Fig. 4(c) considering all w. However, only Industrial, scientific
and medical (ISM) frequency bands are acceptable to consider
for research purposes. Here, the central frequency values of
ISM are 6.78 MHz, 13.56 MHz, 27.12 MHz, 40.68 MHz etc.
Therefore, the optimal fc is considered as 13.56 MHz at w = 2
mm. The summary of the above design procedure to develop a
Tx coil antenna is provided in the flow chart as demonstrated
in Fig. 5.
E. Rx coil selection
The Rx coil is selected based on the application scenario.
The maximum dimension (2b), and number of Rx coil turns
(Nr ) are optimized to attain user desired output voltage Vout .
The application scenario selected in this work is intended for
the drone system available in the test facility that requires a
charging voltage ranging from [22.2 − 24] volts. Thereby, the
parametric sweeping of the Rx coil is targeted to achieve the
desired voltage range. To perform parametric sweeping based
on Vout , the analytical equation of Vout is formulated using
Faraday’s law of electromagnetic induction as [18]
Vout = jωc Nr
ZZ
HdA.
(4)
A
Wherein, A is the effective area of the Rx coil. The parametric
variation of Vout with different dimensional values of 2b is
shown in Fig. 6(a). Here, the Rx turns are fixed at Nr = 1
as further increase overshoots the desired Vout . Further, by
observing the data shown in Fig. 6(a), the 2b value is optimized
in the range [112, 116] mm based on desired Vout range. Here,
the optimal Rx coil dimension is selected as 2b = 116 mm.
Moreover, the optimal 3D voltage profile distribution is plotted
in Fig. 6(b).
III. S IMULATED R ESULTS OF R ESULTANT WPT SYSTEM
The layout of resultant Tx-Rx coils is shown in Fig. 7 and
the optimal dimensional parameters are listed in Table I. MoreTABLE I
T HE PARAMETERS OF T X -R X COILS
Physical dimensions of the Tx-Rx coils
2a/2b/h/w
127.2 mm / 116 mm / 50 mm /
Nt /Nr /fc
5 / 1 / 13.56 MHz
2 mm
over, the simulation results of H-field distribution corroborates
with the analytical results as shown in Fig. 8. The input-output
This
paper's
copyright
is held
by the
author(s).
It is published
in theseonproceedings
and atincluded
in any
suchRestrictions
as IEEE Xplore
Authorized
licensed
use limited
to: Indian
Institute
of Technology
(Ropar). Downloaded
September 12,2023
16:01:47 UTC
fromarchive
IEEE Xplore.
apply.
under the license granted by the "Agreement Granting EurAAP Rights Related to Publication of Scholarly Work."
INPUT POWER SUPPLY
FULL BRIDGE INVERTER
AC-DC RECTIFIER
FILTER CIRCUIT
LOAD
Fig. 9. Circuit analysis of WPT system using LT-Spice simulator.
Diode voltage (VD)
MOSFET blocking voltage(VD)
DC output current (Idc)
DC output voltage (Vdc)
Rx output voltage (VRX)
Input voltage (Vin)
Rx output current (IRX)
Tx current (ITX)
Fig. 10. Wave-forms of various signals of proposed WPT system.
signals (both current and voltage) across different components
of WPT system are determined through LT-Spice simulator.
Further, using these signals the performance parameters such
as output power (Pout ), link efficiency (ηlink ), and system efficiency (ηdc−dc ) are evaluated to test the quality of the resultant
WPT system. The circuit simulation begins by knowing the
circuit-parameters such as Rt , Rr , Lt , Lr , M , and coupling
coefficient (k) which are obtained from EM simulator and are
listed in Table II. The circuit parameter values depicted in TaTABLE II
C IRCUIT PARAMETERS OF WPT SYSTEM
Rt /Rr /Lt /Lr
Ct /Cr /M/k
Circuit parameters
0.83Ω / 0.115Ω / 8.81µH / 0.43µH
15.63pF / 0.32nF / 0.31µH / 0.15
ble II are used in LT-Spice simulator as shown in Fig. 9. Here,
in Fig. 9, the circuit schematic constitutes of input voltage
(Vin ), full bridge inverter circuit consisting of four MOSFET
switches, Tx-Rx coil parameters, full bridge AC-DC rectifier
circuit composing of four diodes, filtering capacitor (CF ), and
load resistance (RL ). The inverter is excited with Vin = 36
volts using a dc source. Thereby, the signal wave-forms such
as Tx coil current IT x , Rx coil current IRx , Rx coil voltage
VRx , DC output voltage Vdc , DC output current Idc , MOSFET
blocking voltage VM OSF ET , and diode blocking voltage VD
as shown in Fig. 10. The input power, Rx coil power, and DC
power are evaluated as Pin = Vin × IT x = 35.34 × 0.862 =
30.46W, PRx = VRx × IRx = 23.04 ∗ 1.24 = 28.57W,
and PDC = Vdc × Idc = 22.33 × 1.11 = 24.78W. The
link efficiency (ηlink ) is defined as ratio of PRx and Pin ,
which is evaluated as 93.7%. Here, the ηlink resembles the
performance of Tx-Rx coils and does not include the effect of
system components such as rectification and filtering circuits.
In contrast, the dc-dc efficiency or system efficiency (ηdc−dc )
is characterized as ratio of PDC and Pin , which includes all
the system losses of WPT system and is found to be 81.3%. All
the performance parameters resulted using LT-spice simulator
using Fig. 10 are summarized in Table III.
A. Limitations and future works
This work’s proposed methodology to design an efficient
Tx coil antenna is limited to a perfectly aligned Rx coil.
This
paper's
copyright
is held
by the
author(s).
It is published
in theseonproceedings
and atincluded
in any
suchRestrictions
as IEEE Xplore
Authorized
licensed
use limited
to: Indian
Institute
of Technology
(Ropar). Downloaded
September 12,2023
16:01:47 UTC
fromarchive
IEEE Xplore.
apply.
under the license granted by the "Agreement Granting EurAAP Rights Related to Publication of Scholarly Work."
TABLE III
P ERFORMANCE PARAMETERS OF THE WPT SYSTEM
Signal and performance parameters
Vin /IT x /VRx /IRx
36 v / 0.862A / 23.04v / 1.24A
Vdc /Idc /VM OSF ET /VD
22.33v / 1.11A / 36v / 22.97v
Pin /PRx /PDC
30.46W / 28.57W / 24.78W
ηlink /ηdc−dc
93.7% / 81.3%
Note:
IT x , VRx , IRx are RMS value
Note:
Vdc , Idc are average value
Note:
VM OSF ET , VD are peak values
Therefore, the applications prone to the misalignment are not
considered in the current work. However, the misalignment
problems are mitigated by ensuring a stable coupling coefficient k. It is observed that at high Qt , it becomes very
challenging to design a Tx-Rx coil that stabilizes the variation
of k as the freedom to increase the number of turns in the
Tx coil severely limits. Therefore, the authors are directing
forward in their future works to design Tx-Rx coils that can
be realized with a minimum number of turns to attain stable
k at high Qt .
IV. C ONCLUSION
The article gives a step-by-step procedure to design a Tx
coil antenna for a near-field WPT system. Here, the proposed
design procedure states the justification for selecting each
Tx coil antenna’s dimensional parameter. As an example,
this article tests the design procedure by adopting a drone
application. The analytical magnetic field distribution of the
resultant Tx coil antenna is verified using an EM simulator.
Moreover, the WPT system’s performance outlined in the
proposed design procedure is analyzed by determining link efficiency ηlink = 93.7% and system efficiency ηdc−dc = 81.3%
using LT-spice circuit simulator.
ACKNOWLEDGEMENT
This work was supported by SERB, Department of Science & Technology, Government of India under Grant
CRG/2022/007257.
[6] T.-H. Kim, G.-H. Yun, W. Y. Lee, and J.-G. Yook, “Asymmetric Coil
Structures for Highly Efficient Wireless Power Transfer Systems,” IEEE
Transactions on Microwave Theory and Techniques, vol. 66, no. 7,
pp. 3443–3451, 2018.
[7] M. Schiestl, M. Brandl, A. Lösch, and R. Stärz, “Design of Transmitter
Coil Antennas for Inductive Resonant Power Transfer,” in 2018 IEEE
Wireless Power Transfer Conference (WPTC), pp. 1–4, 2018.
[8] T. S. Pham, T. D. Nguyen, B. S. Tung, B. X. Khuyen, T. T. Hoang,
Q. M. Ngo, L. T. H. Hiep, and V. D. Lam, “Optimal frequency for
magnetic resonant wireless power transfer in conducting medium,”
Scientific Reports, vol. 11, no. 1, pp. 1–11, 2021.
[9] J. P. W. Chow, N. Chen, H. S. H. Chung, and L. L. H. Chan,
“Misalignment tolerable coil structure for biomedical applications with
wireless power transfer,” in 2013 35th Annual International Conference
of the IEEE Engineering in Medicine and Biology Society (EMBC),
pp. 775–778, 2013.
[10] J. P. W. Chow, N. Chen, H. S. H. Chung, and L. L. H. Chan,
“An Investigation Into the Use of Orthogonal Winding in Loosely
Coupled Link for Improving Power Transfer Efficiency Under Coil
Misalignment,” IEEE Transactions on Power Electronics, vol. 30, no. 10,
pp. 5632–5649, 2015.
[11] Q. Wang, W. Che, M. Mongiardo, and G. Monti, “Wireless Power
Transfer System With High Misalignment Tolerance for Bio-Medical
Implants,” IEEE Transactions on Circuits and Systems II: Express Briefs,
vol. 67, no. 12, pp. 3023–3027, 2020.
[12] C. Cai, J. Wang, H. Nie, P. Zhang, Z. Lin, and Y.-G. Zhou, “EffectiveConfiguration WPT Systems for Drones Charging Area Extension
Featuring Quasi-Uniform Magnetic Coupling,” IEEE Transactions on
Transportation Electrification, vol. 6, no. 3, pp. 920–934, 2020.
[13] C. Rong, X. He, Y. Wu, Y. Qi, R. Wang, Y. Sun, and M. Liu,
“Optimization Design of Resonance Coils with High Misalignment
Tolerance for Drone Wireless Charging Based on Genetic Algorithm,”
IEEE Transactions on Industry Applications, pp. 1–1, 2021.
[14] C.-Y. Chu, S. Huh, S. Choi, J.-H. Park, S. Ahn, S.-G. Lee, and K.B. Park, “Wireless Power Transfer System Design for Electric Vehicle
Charging Considering A Wide Range of Coupling Coefficient Variation
Depending on the Coil Misalignment,” in 2021 24th International
Conference on Electrical Machines and Systems (ICEMS), pp. 732–737,
2021.
[15] F. Zhao, J. Jiang, S. Cui, X. Zhou, C. Zhu, and C. C. Chan, “Research on
Bipolar Nonsalient Pole Transmitter for High-Power EV Dynamic Wireless Power Transfer System,” IEEE Transactions on Power Electronics,
vol. 37, no. 2, pp. 2404–2412, 2022.
[16] H. Wang, U. Pratik, A. Jovicic, N. Hasan, and Z. Pantic, “Dynamic
Wireless Charging of Medium Power and Speed Electric Vehicles,” IEEE
Transactions on Vehicular Technology, vol. 70, no. 12, pp. 12552–12566,
2021.
[17] J. C. Lin, “Safety of Wireless Power Transfer,” IEEE Access, vol. 9,
pp. 125342–125347, 2021.
[18] M. N. Sadiku and S. V. Kulkarni, Principles of electromagnetics. oxford
university Press, 2009.
R EFERENCES
[1] Y. Jiang, L. Wang, Y. Wang, J. Liu, M. Wu, and G. Ning, “Analysis,
Design, and Implementation of WPT System for EV’s Battery Charging
Based on Optimal Operation Frequency Range,” IEEE Transactions on
Power Electronics, vol. 34, no. 7, pp. 6890–6905, 2019.
[2] C. Cai, J. Wang, H. Nie, P. Zhang, Z. Lin, and Y.-G. Zhou, “EffectiveConfiguration WPT Systems for Drones Charging Area Extension
Featuring Quasi-Uniform Magnetic Coupling,” IEEE Transactions on
Transportation Electrification, vol. 6, no. 3, pp. 920–934, 2020.
[3] S. Wang, Z. Hu, C. Rong, C. Lu, J. Chen, and M. Liu, “Planar MultipleAntiparallel Square Transmitter for Position-Insensitive Wireless Power
Transfer,” IEEE Antennas and Wireless Propagation Letters, vol. 17,
no. 2, pp. 188–192, 2018.
[4] N. Ha-Van and C. Seo, “Butterfly-Shaped Transmitting Coil for Wireless
Power Transfer System in Millimeter-Sized Biomedical Implants,” in
2018 IEEE Wireless Power Transfer Conference (WPTC), pp. 1–4, 2018.
[5] B. J. Varghese, T. Smith, A. Azad, and Z. Pantic, “Design and optimization of decoupled concentric and coplanar coils for WPT systems,”
in 2017 IEEE Wireless Power Transfer Conference (WPTC), pp. 1–4,
2017.
This
paper's
copyright
is held
by the
author(s).
It is published
in theseonproceedings
and atincluded
in any
suchRestrictions
as IEEE Xplore
Authorized
licensed
use limited
to: Indian
Institute
of Technology
(Ropar). Downloaded
September 12,2023
16:01:47 UTC
fromarchive
IEEE Xplore.
apply.
under the license granted by the "Agreement Granting EurAAP Rights Related to Publication of Scholarly Work."