This document provides an overview of wireless power transfer through magnetic induction. It discusses the technology's potential benefits, such as reducing electronic waste and improving energy efficiency compared to wired charging. Current applications of wireless power include charging stands for smartphones, computer mice, and envisioned uses in electric vehicles and medical implants. Standards organizations have developed specifications to ensure compatibility between wireless power devices. The document also provides background on the physics principles behind wireless power transfer, such as electromagnetic induction and alternating current circuits.

1. 1
Wireless Power through Magnetic Induction
Nathan Baughman
UW – Eau Claire
August 18th
, 2017

2. 2
Introduction:
Imagine a modern household filled with the up to date technologies and devices.
Anything from a brand new 4K flat screen TV, a Samsung galaxy smartphone, and even a small
LED multi colored desk lamp. What’s interesting about this home, however, is that none of these
devices are plugged in. Neither are they dependent on batteries, but they all appear to be
turned on. These devices are in fact being powered wirelessly. A small wireless transmitter is
stationed somewhere near the center of the house sends out a magnetic signal which is tuned
to all of the devices in the house. This family never has to worry about finding an outlet to plug
something in, worrying about mobile devices dying while moving around the house, or filling up
their garbage with dead batteries or broken chords.
While this scenario seems like it comes straight from a science fiction novel or from the
fantastic mind of Nikola Tesla, it may not be as farfetched as it seems with today’s advances in
technology. With a phenomena known as magnetic induction, which Nikola Tesla did indeed
study and implement in some of his later inventions, companies are developing technology to
charge or even perpetually power devices without the need of cables or batteries. Two common
methods that inventors use when creating wirelessly powered devices are called the inductive
method and the resonance method, although both methods use magnetic induction.
One image of an exemplary technology is a phone charger where the phone is placed
on top of some sort of substrate which, through induction, charges the device’s battery without
needing to be plugged in. Devices such as these do already exist and are in the mainstream.
And they do not only exist for phones, but are designed for other electronics too. Many
scientists and inventors envision that wireless power will continue to blossom and extend to
beyond hand-held electronics to large scale usage like in vehicles and hospitals.
What Tesla and other inventors define as wirelessly powered is different from something
that is mobile or portable. A mobile device, like a cell phone, can operate without any sort of
connect and is commonly powered by a battery. However, a device like this must be plugged in
or connected periodically to recharge the battery powering the device. Wireless power suggests
that a device can be perpetually powered while never requiring a connection for power through
some means of transmission. This means that the transmission is used to directly power the
device. Something can also be wirelessly charged, which means that the wireless transmission
powers the battery which then powers the device. Still, there is never a need to have a physical
connection at any time. What this paper addresses are the two latterly mentioned ideas:
Wireless power and wireless charging.
This paper is segmented into two main parts. The first is a review of literature that
discuss the ethical and environmental impact of wireless power, as well as contemporary and
upcoming technology. The second part is an analysis of the physics behind wireless power. It
encompasses areas of electromagnetism, electronics, and some engineering.

3. 3
Part 1: Practical Aspects of Wireless Power
1.1) Green Electronics
With the world’s growing usage of electronics in almost every avenue of business,
entertainment, healthcare, transportation, and other areas, the exigence to further the
sustainability and environmental friendliness of electronics also continues to arise. The increase
of electronic waste, or E-waste, is becoming a greater threat to the environment with concerns
of its harm to the environment and human health. According to the Public Reference Bureau,
approximately 40 million metric tons of E-waste is generated every year globally, with only 13%
of it being recycled. Of the 40 million, 9 million metric tons are composed of televisions,
computers, cellphones, and other electronic devices. The risks that these pose to human health
include pulmonary and cardiovascular disease from the toxic metals, such as lead, being
released into the environment. There is also evidence of E-waste creating a risk for lead
poisoning and contaminating farms. The majority of these chemicals are not biodegradable, so
the risk only increases over time as more and more waste is generated [1]
.
One of the ways humans can mitigate the massive production of E-waste is by changing the
way in which we power our devices. Alongside devices themselves contributing to E-Waste,
another source coming from modern electronics are throwaway batteries and power
chords/charging cables. There are 40 billion disposable batteries manufactured every year,
which leech toxic and lead acid after eroding in landfills, possibly poisoning neighboring water
supplies [2]
. Some batteries also expose landfills to nickel and cadmium, which are also very
toxic. Wireless power completely circumvents the harmful waste produced from batteries. The
methods for wireless power known today generate virtually no wasteful materials such as
batteries and wires, dramatically decreasing the amount of toxins dispersed into landfills.
Energy inefficiency is another source of waste in modern commercial electronics. Devices
and technologies that are not energy efficient waste energy in powering, often times to joule
heating in wiring or charging. According to Texas Instruments’ analysis of their own systems, a
current wired charger has a total system efficiency of about 68% to the charger. In other words,
68% of power is used to transmit electricity while the other 32% is lost due to heat or other
mechanisms. In TI’s wired charger, however, efficiency to the battery is about 57%. As a result,
the total system efficiency is 39%. In a wireless powered system, energy transfer is only to the
charger. TI found that their wireless power evaluation modules system had a total 60% [3]
.
Wireless power is therefore more efficient than most wired power, in that it maximizes use of
generated energy [2]
.
Greenhouse Gas Reduction: Research into wireless power extends beyond mobile devices
and small electronics. In fact, it has an application in vehicular transportation. Electric Vehicles
are being developed in many countries such as South Korea, and applications of wireless power
make electric vehicles a significantly more viable enterprise. This inherently has benefits by
reducing greenhouse gas emissions that normal fossil fuel powered cars produce, as well as
fossil fuel usage. For example, the Transit Investments in Greenhouse Gas and Energy
Reduction is a program implemented by the Federal Transit Administration. Its objective is to
improve the current state of greenhouse gas emission and energy usage. It funds many projects
invested in wireless power technology for public transportation usage, such as the University of
Utah’s Advanced Vehicle Electrification and Howard County’s Transit Authority electric bus
retrofit. In the programs first report, annual estimated greenhouse gas savings for the program

4. 4
totaled more than 63,700 tons CO2, which adds up to more than 411,700 tons CO2 over the life
of the program. The FTA also strives in many ways to outfit public transportation with electric
power. Their reports show that since 2011, over 35% of public transportation features
alternative fuels, all of which can benefit from wireless power [4]
.
1.2) Popular Technology
Wireless power is available today for any consumer in many forms of technology. In fact,
it has been around for several years in devices that perhaps were not completely obvious. Oral-
B has been using wireless charging in some of the toothbrushes since the 1990s (albeit in a
very simple form). Similarly, Energizer created a wireless charging station for the Nintendo Wii
remote in 2009. Now, with portable devices flourishing in consumer culture, wireless power
integration continues to enter the mainstream day after day in numerous size and capability.
Here are a few examples of some devices that utilize wireless power.
Computer Mouse: On a smaller scale, wireless power has been developed to be
compatible with a computer mouse. After four years of development, Logitech is releasing a
wirelessly powered mouse that negates any battery or wire dependence. It is designed with
magnetic resonance that can power a static or moving mouse, which means that a user does
not need to place their mouse on small area in order for it to charge. Its basic operation consists
of a “power core module,” which receives the magnetic signal created by a 2 mm thick charging
base below the mouse mat [5]
.
Smartphones: According to the Wireless Power Consortium, there exists already 70
models of phones that use wireless power in some way. This is coming from companies such as
Samsung and Apple. In fact, both Apple and Samsung just recently patented their own
respective wireless charging cases that fit onto their phones. Since both companies belong to
the Wireless Power Consortium, their devices adhere to the “Qi” standard of wireless power
which will be discussed in more detail later [6]
.
Robotics and Unmanned Systems: Wireless power has many advantages when used
with unmanned systems, such as logistics robots or drones. The lack of any physical connection
points for power creates clear advantages. One includes unlimited mating cycles, or no capacity
to how often something can be charged. Physical connection for power often results in
degradation over time on a connection point. This extends to almost all other wired devices.
Similarly, there is no worry of misalignment when connecting to power [7]
.
With no need for connected power, one can also help to design a robot that is more
waterproof or otherwise environmentally protected, since the components of wireless power
transfer to not need to be exposed in any way. With corded power, exposed connection points
or sockets are exposed to dirt, dust, and water ingress [7]
.

5. 5
1.3) Future Technology
There still exists much potential for wireless power. Earlier in this paper, it was
mentioned wireless power’s growing use in smartphones and robotics. One area where it has
not quite yet hit widespread use is in transportation. However, recent developments at Stanford
University in wireless power have brought more plausibility to the prospect of powering cars and
other vehicles. As of June 14th
, 2017, researchers at the university developed a system that
wirelessly transmits electricity into a nearby moving object. Their system uses magnetic
resonance, but is composed of two identical coils eliminating the need for complex tuning. If
pursued, this system could eventually be used to power a moving car as it drives along the
road. Transmitter could be placed beneath roads, which would then be able to power moving
cars. Their system was able to light a small LED, although for a larger device such as a car, this
would need to be scaled up a considerable amount [8]
.
Charging Smartphones at long distances: Most wirelessly powered smartphones
currently in the mainstream utilize magnetic induction in their components, as opposed to
magnetic resonance (also known as resonant coupling). The differences in the physics behind
these two concepts will be discussed further in this paper. The overarching difference is that
magnetic resonance allows for a device to be much further away from the transmitting coil and
still be able to charge. Most devices now have to be placed near the transmitter (usually on top
of it) in order to charge. A mobile device that is powered via resonant coupling could be charged
at a distance throughout a person’s home, a hotel, restaurant or other public area.
Medical Implants: Wireless power certainly has its promise in hospitals for medical
related purposes. One can imagine a hospital a room that is much more hygienic and practical
without nests of wires and connectors being used to power medical devices, like in figure 1.3
taken from Proxi by Power’s website.
Figure 1.3
Already, though, hospitals are beginning to develop wireless power. At MIT, researchers
have for the past several years been looking into developing ingestible electronics including
sensors that can monitor vital signs, and drug delivery vehicles that can remain in the digestive
tract for weeks or months. While at first these ingestible were not thought to be wirelessly
powered and were originally powered using galvanic cells which loose power over time. The
developers realized the most practical way for these devices to be designed is to have them be
wirelessly powered. Wired power would not be possible and battery power will eventually run

6. 6
down could pose potential health risks [9]
. At MIT, they have already developed the blueprints for
their wirelessly powered device but have yet to put it into practice. The new method has the
potential to monitor heart rate, temperature, or levels of particular nutrients or gases in the
stomach [9]
.
1.4) Consumer standards
With the growth of wireless power, there becomes a growing issue of device
compatibility. In order for wireless power to be more ubiquitous, specifications need to be
common among all devices that utilize wireless power. The lack of a standardized system
brings forth the possibility of some dangers, such as overheating and device damage. This
is comparable to Universal Serial Bus, or USB, an industry standard for connected/wired
power.
A large equivalent for wireless power is the “Qi” standard, which was developed by the
Wireless Power Consortium, or WPC. Qi standardizes devices and charging pads that use
magnetic inductive coupling. Some companies that belong to the consortium, which
implement Qi standards in the wirelessly powered device, are Asus, Samsung, and HTC.
The Wireless Power Consortium has a written rather extensive guidelines for the
construction of device that are to be “Qi” certified. Once they are certified, they are to be
advertised as so and it is assumed that they are compatible with any other “Qi” certified
device. The specifications are made so that their devices can be either low or medium
powered, meaning that a device can administer up to 5 W for low power and 120 W for
medium power. Specifications differ across different categories of devices, for instance,
automotive chargers versus phone chargers. The specifications are available on the
Wireless Power Consortium website [17]
.
Similarly, The AirFuel Alliance is another non-profit consortium that creates standards for
wireless power. Their specifications address the same issues of power, frequency, and
current/voltage limitations for particular device. As with the Wireless Power Consortium, their
standards are free to download on their website. Companies that belong to this consortium
include Dell, Boene Technology, Sony Corporation, and many others [19]
.
Comparatively, WPC is a larger consortium than AirFuel Alliance, with about 235
members as opposed to 150. The former also has many more products in the market. This
could be attritubed to the scope of both consortia’s market, as WPC focuses on phones and
industry while AirFuel Alliance focuses on phones and tablets 8]
. It is intriguing to wonder
how these two standards will shape the market, and what ground-breaking devices will be
created with their guidance.

7. 7
Part 2: Physics of Wireless Power
2.1) Basics of Circuitry
It is important to note that the following sections discuss modern designs and
development of wireless power setup. Thus, some knowledge in electronics or electrical
engineering is fundamental in understanding the topics. This section will describe some
electronics concepts to serve as somewhat of a preparation for the upcoming sections.
Direct Current Circuit: A direct current (DC) circuit is composed of electrical conductors
that connect a point of high electrical potential to a point of lower potential, causing electric
current to flow. This is conventionally thought of as positive charges moving through the circuit,
but in reality are negative charges. A common element of a DC circuit is a resistor, which limits
the flow of current. The majority of wires used as conductors, such as copper wire, have
inherent resistance but it often negligible in comparison to a circuit components (such as a light
bulb) perhaps made of carbon.
𝑉 = 𝐼𝑅
Equation 2.1
Equation 2.3, Ohm’s law, shows that the value of electrical potential or voltage (V) is
equal to the product of the current in Amps and resistance in Ohms.
Alternating Current Circuit: Current does not always have to flow in one direction in a
circuit, it can oscillate or flip directions at some frequency. This is the kind of current that is
present in power lines that bring electricity to homes and larger infrastructures. These types of
circuits that use alternating current are called AC circuits. Like DC circuits, they are composed
of conductors and resistors, but also elements called inductors and capacitors. Inductors are
represented as L and capacitors as C. So, AC circuits composed of all three elements are
denoted as RLC circuits, to denote that all three types of elements are included in the circuit.
The main purpose of AC circuits is to quickly and conveniently transmit electricity over great
distances. This is why power lines are used carrying AC current. However, AC current is also
present on smaller scales in things like electric motors.
2.2) Electromagnetism
Surrounding any magnetic is a magnetic field, which can exert the force of magnetism
on a certain objects. A magnetic field can also be created from something, say a wire, with
moving charge. The fact that a magnetic field can interact with a conductive material to produce
electricity is a fascinating and advantageous notion, but it is not entirely exotic. Physicists
Michael Faraday and Joseph Henry began independently studying the connection between
electricity and magnetism in the early 1800s. Their findings led to what is known today in
regards to electromagnetism, and largely factor into what makes wireless power possible.
A key phenomenon relating to Faraday and Henry’s research is electromagnetic
induction. Electromagnetic induction, in short, is when a changing magnetic field interacts with a
coil of wire to produce a voltage. In a simple experiment, one could demonstrate
electromagnetic induction by pushing and pulling a bar magnet through a coil of wire hooked up

8. 8
to a voltmeter, which would show increase in voltage. The voltage level would increase with a
greater number of loops in the wire, or a faster movement of the magnet.
There are several other concepts that resulted from further into electromagnetism that
help to explain how wireless power is possible. Thus it is helpful to define a few of them first
before going further into wireless power.
 Ampere’s Law
A magnetic field is produced in the space around electric current which is
proportional to the electric current. Ampere’s law illustrates this proportionality in the
equation:
∑ 𝐵||∆𝑙 = 𝜇0 𝐼
Equation 2.2
Which states the sum of the magnetic field magnitude (BII) and its length’s (Δl)
product is equal to the product of permeability (μo) and the value of the current (I) [10]
.
 Faraday’s Law
When there is a change in the magnetic field around a coil of wire, a voltage is
induced in the coil of wire regardless of how the change is made. The voltage can be
characterized by the following equation, derived from Maxwell’s Equations:
𝐸𝑚𝑓 = −𝑁
∆𝛷
∆𝑡
Equation 2.21
In short, the rate of change of magnetic flux (∆Φ ) multiplied by the number of
turns (N) in said wire produces the value of the induced voltage, or emf. The
negative sign is a result of Lenz’s Law [10]
.
 Lenz’s law
The polarity of an induced voltage resultant from Faraday’s Law produces a
current with a surrounding magnetic field (Ampere’s Law) which opposes the
magnetic field of that which created it. This is so that the total change of magnetic
field in a loop of wire is always kept constant. In Faraday’s law, the negative sign
denotes this principle [10]
.
 Transformers
An ideal transformer helps to model how wireless power transfer works. It utilizes
the same principles that wireless power configuration (which will be described later)
does. They are not typically referred to as wireless, but in reality in actually do carry
electric energy across empty space.
However, transformers are used to step up or step down in voltage, rather than
transmit power. They are also composed of windings, which are electrical conductors
wound around a magnetic material.
Nevertheless, it is useful to examine a transformer. A transformer is comprised of
two sets of windings; the primary, which receives the power, and secondary to which

9. 9
the power is delivered. The AC source powering the transformer creates alternating
current in the primary windings, which sets up an alternating magnetic flux. The
magnetic flux passes through the secondary windings, and through induction
generates a voltage and current passes through the second circuit [10]
. The core
within the windings helps to intensify the value of the magnetic field as well as
concentrate it. This allows more of the magnetic field to pass through the secondary
windings.
Figure 2.2
Figure 2.1 illustrates how an alternating current Ip with a voltage magnitude Vp
powers the primary windings Np. It transfers over to the secondary windings Ns via
induction and induces a voltage (emf) Vs with a current Is based on the load
resistance R.
The ratio of the secondary to primary voltages is proportional to the ratio of
windings of the aforementioned. It can represented by the following equation:
𝑉𝑠
𝑉𝑝
=
𝑁𝑠
𝑁 𝑝
Equation 2.13
Where, in Equation 2.13, V is voltage and N is the number of windings. P and
S denote the primary and secondary systems respectively.
2.3) Magnetic Induction Method for Wireless Power
As of today, there are effectively two main methods that are used in wireless technology.
They are wireless power through magnetic induction, and wireless power through magnetic
resonance. Both methods are closely related, although the latter is effectively a more
complex iteration of the former. Therefore, both methods are worth examining separately to
understand their differences.
The first and more developed method is with the use of magnetic induction. Faraday’s
law of induction predicts that a changing magnetic field, flux, is able to generate an electric
current in a loop of wire. This the basis of how an ideal transformer functions. It is also how
engineers design wirelessly powered technology, where one transmitting coil creates an

10. 10
oscillating magnetic field through another receiving coil which generates electric current and
powers said devices [11]
. The magnetic field in this setup is highly concentrated. This means
that there is very little leakage, but the range is limited to only a few centimeters [18]
.
The percentage of how much magnetic field is turned into electric power is based on the
separation of coils and the relative sizes of the coils [11]
.
Figure 2.3
Figure 2.3 shows how the magnetic field (the thin lines) from the transmitter coil
penetrate the receiver coil. When the coil distance is much smaller than the coil diameters
(assuming they are equal), the system is denoted as tightly coupled, meaning the coupling
factor is high.
The coupling factor refers to what fraction of magnetic flux from the transmitter
penetrates the receiver coil. A high coupling factor indicates an efficient transfer, less loss of
energy, and less heating. Something with a high coupling factor can also be referred to as a
tightly coupled. The Wireless Power Consortium, which develops specifications standards
for wireless power, defines a coupling factor as a coefficient K, with a value between 0 and 1
(0 being no penetration and 1 being complete penetration). Typical values are between 0.3
and 0.6 for devices using magnetic induction. The value is determined by the coils’
separation and their individual sizes. If the coils are not parallel then the coupling factor is
influenced by the angle between them [12]
.
𝑘 =
𝐿12
√ 𝐿11 ∗ 𝐿22

11. 11
Equation 2.3
Equation 2.3 shows the definition of the coupling factor, using the inductances of the first
and second coils (L11 and L22) and the coupling inductance L12
[13]
.
Another way to describe the coils in a given system is by their quality, or Q, factor. This
is a ratio of inductance to resistance of a given coil, shown in the following equation:
𝑄 =
2𝜋𝑓𝐿
𝑅
Equation 2.31
Where L is the inductance, R is resistance, and f is the frequency of AC current. The
values range from 0 to infinity, although values past 1000 are difficult to produce. Most
values for devices created in mass quantity are around 100. Engineers take this aspect in to
consideration when designing a specific device because it contributes to the efficiency of the
power transfer [14]
.
Figure 2.31
Figure 2.31 is taken from the Wireless Power Consortium’s website, and shows the
division between their denotation of good and bad efficiency. With a Q factor of 100, a
common value, efficiency changes with an increasing axial distance and size of coils. Note
that Q is consonant in this graph. With a greater Q, the “good” region would shift
downwards, and conversely would shift upwards with a lower Q. The different curves
represent size differences in coils, expressed as a ratio. For example, no size difference is 1
and a size difference where one coil is 1/10 the size of the other (either transmitter or
receiver) is 0.1. The graph shows that a lesser size difference results in a greater efficiency.

12. 12
Figure 2.32
Figure 2.32 depicts a flowchart of a typical wirelessly charging system. After the AC line
is converted into DC, it powers a carrier oscillator and a power amp. The carrier oscillator
produces an AC signal at a suitable frequency to power the transmitter coil. The power amp
boosts the signal level to supply adequate power to the receiver, and the matching network
ensures that there is no feedback in the system. Signaling occurs so that that the power
amp knows exactly how much to boost the AC signal. After the receiver coil picks up the
transmitter magnetic field, the resultant signal is rectified (turned into DC current) and
regulated to a safe voltage level which can then power a charger load. Signaling occurs
again so that the regulator knows exactly what voltage level to produce after the AC signal is
rectified [20]
.
2.4) Magnetic Resonance Method for Wireless Power
A shortcoming of the ‘inductive’ approach of magnetic induction is that power transfer
rapidly diminishes after a few centimeters separation as a result of magnetic field flux
decrease. Researchers at the Massachusetts Institute of Technology, MIT, developed a
technique, using magnetic resonance, which maintained a constant level of power transfer
over a range of distances. The system involves power transfer between two coils operating
at resonating frequencies, determined by capacitance, resistance, and inductance.
Magnetic Resonance technically still involves magnetic induction. However, it is comprised
of coils that are tuned to one another so that the receiver “resonates” with the transmitter
and power transfer can occur over greater distances [11].
In the configuration, the transmitter and receiving coils are built so that they have a
matching resonant frequencies. The resonant frequency is the frequency which produces
the largest current given a source voltage. In an RLC circuit, this depends on the impedance

13. 13
values of inductors, resistors, and capacitors in the circuit. This is similar to how radios can
tune to different frequencies, based on radio wave frequencies [10]
.
In a wireless power transfer via resonant coupling, the functionality is quite analogous to
a circuit that receives radio waves. However, the difference is that the transfer in energy is
through a magnetic near field rather than an electromagnetic radio wave. The tuning
aspects take place in both the circuitry and the physical construction of the coupled coils.
When oscillating current moves within primary coils, a resultant oscillating magnetic field
is produced. The magnitude of the magnetic field drops substantially within a short distance
of the primary coils. A secondary coil can still pick up the magnetic field if it is tuned to
resonate at the frequency of the primary’s oscillation at a considerable distance. All that is
necessary is for the secondary coil to receive some of the field, and most of the energy can
be transferred. Both coils are loaded with a capacitor so that they are both LC circuits, giving
them the capability to have a resonant frequency.
In wireless power transfer, the resonating frequency is influenced by the number of
number of turns in the coil, diameter of each turn, and diameter of the coil itself. It is also
influenced by the material of the coil [15]
. In some more complex configurations, the
transmitter also goes through a second transmitting coil to help with unidirectional
propagation of the magnetic field, similar to an antenna.
Figure 2.4
Figure 2.4 shows the oscillator attached to the transmitter coil. The magnetic field
spreads out and attenuates the resonant ‘receiver’ circuit. The range of the magnetic field is
influenced by the quality “Q” factor of the transmitting coil, mentioned early in section 2.3.
The current produced in the receiver is of the same frequency of the oscillator, such as 10

14. 14
MHz like in experiments conducted at MIT. This basic version of the magnetically coupled
circuits also has a rectifier in the receiver coil, which indicates AC to DC conversion.
Figure 2.41
In figure 2.41, circuit a) shows a simplified circuit of a transmitter coupled with a receiver
via resonance. Circuit b) shows generally how stray inductances could be eliminated [16]
. As
it can be seen, Ltx and Lrx, the transmitter and receiver inductor respectively, are loaded with
capacitors CpTx and CsRx. This gives both circuits L-C properties, including resonance. The
second circuit has a load resistance RL, which could for instance be a phone charger.
Since, in this method, there is sort of a network created from the near field around the
transmitter, multiple recievers can be powered from a single transmitter. However, the
number of devices is limited by the maximum power output of the transmitter.

15. 15
Figure 2.42
Figure 2.42 is an image of a power transmitter unit, PTU, powering five power receiver
units, PRU. The image comes from AirFuel Alliance’s “Rezenence” wireless charging
system. The control arrows show that there is back and forth communication between the
receiver and transmitter units to ensure good performance within the system. The system
can transfer up to 50 W at a maximum distance of 50 mm.
Wireless transfer via magnetic resonance, while theoretically very practical and useful, is
still underdeveloped. Its main drawback is that it is far less efficient than magnetic induction.
This happens because of magnetic flux leakage. Researchers at MIT and other institutions
are currently developing more viable technologies.
Conclusion:
Wireless power through induction is in many ways a lucrative field that is continuing to
blossom in our culture’s use of technology. There are many short ranged devices that can
charge or power phones, computer peripherals, and robots that are already out in the
mainstream. Many longer ranged technologies are being developed also. Devices such as
these could provide power with at distances that could encompass an entire home, or perhaps
even a highway. All of these, aside from practical advantageous, are beneficial to the
environment because they reduce the waste generated from batteries and connected required
for non-wireless power.
The core physics behind developing these devices is not wholly groundbreaking. In fact,
the understanding of magnetic induction has been around since the 19th
century. However, with
the current state of technology, more and more of its application is becoming apparent. There

16. 16
are also avenues and aspects of magnetic that is not fully developed and still can be
researched. This includes power transfer through magnetic resonance, which researchers at
institutions like MIT and Cornell are to this day exploring.
In conclusion, the possibilities of what could be developed with wireless power is still
very prosperous. It will be intriguing to examine what breakthroughs will be made, and how they
will impact our knowledge of physics and the current state of the environment.

17. 17
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