1. TEMPLATE DESIGN © 2008
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• Traditional SCMR system requires a certain
distance between the source and the TX resonator,
as well as between the load and the RX resonator
WEARABLE CONFORMAL SCMR SYSTEMS
Karina A. Quintana, John S. Gibson, Stavros V. Georgakopoulos
Florida International University
FIU ElectroMagnetics Lab
10555 W Flagler Street, Miami, FL 33174
Engineering Center, EC 2965
Phone: 305-348-2807
Email: kquin035@fiu.edu, jgibs023@fiu.edu
https://emlab.fiu.edu/
The performance of a compact wearable wireless
power transfer (WPT) system based on the
Conformal Strongly Coupled Magnetic Resonance
(CSCMR) is presented. This wearable CSCMR
system consists of a receiver that is printed on a
circuit board and it is attached to a polyester fabric
band. The high efficiency of this WPT system is
validated through simulations and measurements.
The proposed design does not occupy a large
volume, and can be easily printed on substrates.
Therefore, it is suitable for applications, such as
wearable devices and health monitoring.
Q =
2p frL
R
C =
1
4p2
fr
2
L
h =
Pload
Psource
= S21
2
A wearable conformal SCMR WPT system was
proposed. The performance of this system while it
was worn or not by a user was validated by
simulations and measurements. Our results show
that the efficiency of the antenna in the air is 70%
and on a user’s arm is 50% at a distance of 60 mm.
The compact size and high WPT efficiency of this
CSCMR system can support wireless powering of
wearable devices.
Source Load
TX Resonator RX Resonator
Fig. 2: Schematic of Conformal SCMR system.
Introduction
Source TX Resonator RX Resonator Load
ℓ1 ℓ2
ℓ3
ℓ
Fig. 1: Schematic of traditional SCMR system.
• Embed the source and load elements into the TX
and RX resonators, respectively
Conformal SCMR
• Conformal SCMR system will have high wireless
powering efficiency if the TX and RX elements
resonate at the same frequency
• Q-factor and lumped capacitor must be calculated
using:
• The wireless powering efficiency is calculated
using:
Wearable CSCMR System
• Significantly shrinks volume of traditional
SCMR system to a compact, planar structure
• Easily printed on substrates
• Suitable for printed circuit boards (PCBs)
• Application in wearable devices, implantable
devices, and health monitoring
• A CSCMR system is fabricated on a one-sided
copper FR-4 substrate (ε = 4) with copper
thickness of 0.035 mm and dielectric height of
1.5 mm.
• The load element and the RX resonator are
attached to polyester fabric band that has a
thickness of 4 mm.
Measurements
Fig. 4a: Fabricated CSCMR
system in air.
Fig. 4b: CSCMR system
worn by a user.
• Measured efficiency of the CSCMR system in free
space is 69.8% and simulated efficiency is 80.95%.
Fig. 6: Measured and simulated results of antenna in air.
• Efficiencies of the antenna on the arm are lower
than corresponding efficiencies in air
• Might be due to body losses, Specific Absorption
Rate (SAR), or the effects of the human body on
the CSCMR receiver
Conclusion
Contact Information
Fig. 3: Parameters of CSCMR system.
• Din = 19 mm
• Dout = 32 mm
• d = 60 mm
• w = 6 mm
• ANSYS HFSS simulation model of the CSCMR
system worn by a user includes the two antennas
and a box with the same material properties as the
ones of human muscle
Fig. 5: Simulation model of wearable CSCMR system.
• Measured efficiency of the CSCMR system work
on a user’s arm is 49.37% and simulated
efficiency is 50.72%.
Fig. 7: Measured and simulated results of antenna on arm.