Wireless Charging Technology: All You Need to Know

September 1st, 2016

Wireless charging is the transmission of energy from a power source to a consuming device without wires or cables. This means that all wireless charging technologies are comprised of both a transmitter (or charging station) that transmits that energy and a receiver (integrated inside a device) that receives the energy to charges the battery of the device.

While wireless charging technology may have been in existence for some time, the way we charge our devices is completely new! Let’s have a look at how wireless charging has developed over the years:


The History of Wireless Charging Technology

Danish physicist Hans Christian Oersted originally discovered that electric currents create magnetic fields back in 1820. He passed an electric current through a wire, which caused a nearby magnetic compass to move. What’s more, he also discovered that switching the current would even switch the direction of the compass needle. This wasn’t the first discovery of wireless charging, BUT it was the first occurrence which showed that electricity and magnetism are linked. A decade later, English scientist Michael Faraday found that coiled wireless concentrate the magnetic field enough to induce a magnetic charge in a second coil….and, voila! Electromagnetic inductive wireless charging was born.

Then came the famous Nikola Tesla, who first demonstrated wireless electricity transfer with his Tesla Coil in 1890. To do this, he used a high-frequency alternating current to wirelessly light up a light-bulb from across the room. This method used resonant inductive coupling, which involved tuning two nearby coils to resonate at the same frequency. It has taken over a century, but we are only recently beginning to fully understand how to harness this power and take things to the next level. When referring to wireless power, most refer to inductive coupling or magnetic resonance based on the same basic concept of using coils to create magnetic transfer.

Over time, other forms of wireless charging technology have also developed! Radio Frequency Wireless Charging is one of these. It utilizes radio frequencies transmitted through a wireless charger and picked up by a receiver within the device (not a coil), that is then converted into DC voltage. Other methods of wireless power transmission that are being evaluated and tested out include infrared wireless charging (using infrared lasers) and even ultrasound.

Wireless Charging Technology History


Nonetheless, today the two dominant wireless charging technologies currently in the market: induction and radio-frequency.


How does Magnetic Inductive/Resonant Charging Technology work?

Magnetic inductive/resonant charging technology uses an electromagnetic field generated by a coil to create the charge. By using magnetic coil chargers that are lined up, the first coils will emit an alternating current via a transmitter, while the voltage is induced in the receiver coil that is then used to charge the battery of the device. Essentially, set your phone or watch on a special pad and it immediately begins to charge!

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This type of charging is most commonly seen in the charging pads outfitted at outlets such as Starbucks, or electric toothbrushes – i.e., the powered coil from the mat or stand transfers power (using induction) to the handle of the toothbrush in order to charge the battery.

Magnetic Versus Resonant Wireless Charging Technology

People often talk about magnetic and resonant wireless charging as though they are different when, in fact – they are both types of induction! The main difference between the two lies in the frequency. Magnetic inductive operates at alternating frequencies, providing higher efficiency but very restricting in terms of precise alignment between the coils (needing precise placement for effective wireless power transfer). While resonant wireless charging is achieved when both the transmitter and receiver coils are resonating at the same frequency, allowing for less restriction in terms of alignment but sub-optimal power transfer.

Magnetic Wireless Charging Technology


How does RF wireless charging technology work?

Unlike induction, Radio Frequency wireless charging is a newer technology that has developed to provide a different user experience. Essentially, it utilizes radio frequencies also transmitted through a wireless charger and picked up by a receiver within the device that is then converted into DC voltage. Meaning that effective wireless power transfer does on depend on alignment of the transmitter and receiver or precise placement. Giving users an even easier charging experience, whereby they can simply drop their device and have it charge effectively.

In addition, the transmitter and receiver are not restricted by measurements, allowing RF wireless charging to accommodate devices that induction cannot- i.e., devices that are not large or flat surfaced. Because RF wireless charging has a receiver based mostly on electronic circuitry, and not a coil, it does not have the same physical limitations in size and shape. This allows the receiver to be integrated into the smallest of electronic devices, such as small wearables, hearing aids, and more.

Humavox's wireless charging receiver


Humavox, for example, is an RF-based wireless charging company. To better understand how RF wireless power implementation works, one can evaluate the different component of Humavox’s platform:

Humavox’s Wireless Charging Technology Components

ETERNA Platform:

Humavox’s ETERNA wireless charging technology is a highly accessible wireless charging platform that allows ANY product design of ANY size to easily integrate wireless charging. This way, product designers can mimic the user’s existing usability patterns by integrating wireless charging into nearly any containing object where users already instinctively drop their devices. It’s as easy as dropping a coin in a box!

wireless charging technology for the smallest device

The platform itself is comprised of 3 different parts: Thunderlink, NEST & Eterna Charging Optimizer.

Humavox wireless charging technology

Humavox’s Two Steps to Integration


Thunderlink is ETERNA’s power receiver (Rx module).  In fact, the smallest wireless charging receiver available! Thunderlink can be easily integrated into any device, and combines electronic circuitry and a proprietary RF pickup element in order to enable efficient reception of the RF signal resonated by the NEST transmitter. Unlike other wireless charging technologies, Humavox’s receiver is small and flexible enough to fit into the smallest of electronic devices, without the need for coils. This enables seamless integration into devices such as hearing aids, small wearables, and much more.

wireless charging technology for the smallest device


The NEST is ETERNA’s power transmitter that is a design-free charging station. That means the charging device could potentially be a bowl, cup-holder, drawer…or essentially ANY device. With ETERNA wireless charging technology, the NEST charging station has almost no design constraints… meaning your product designer has complete control over the user experience, functionality, and interface when it comes to charging a device.

drop and charge wireless charging technology


Charging Optimizer

Humavox’s ETERNA Charging Optimizer Algorithm ensures effective coupling in order to perfect the charging process in real-time and utilize energy effectively. Providing users with a true ‘drop and charge’ experience, without the need for precise placement or alignment.

wireless charging technology - Humavox drop & charge

Click here to learn more about Humavox’s technology.

So Why Do We Need Wireless Charging Technology?

The average US family currently owns over 24 electronic devices per household, and this number is rapidly growing thanks to the flourishing wearable market. Yet, while the number of devices grows, so does the number of cords required to charge them. Charging has become a daily hassle that must be resolved with a simple, natural charging solution. That is why an optimal and effective wireless charging technology solution is needed.


The Obstacle to Wireless Charging Technology:

Wireless Charging Technology Standardization

One of the main hindrances to wireless charging becoming mainstream is the lack of devices supporting the same standard. The integration of wireless charging into everyday life requires standardization within the field in order for devices to be compatible on-the-go – whereas current competing wireless charging technologies mean that devices will not work with any type of charging station. In January 2015, two alliances emerged – the A4WP and PMA to form the Airfuel Alliance. Their ultimate goal is to facilitate collaboration between the different technologies, so that end-users won’t even know which technology they’re using to wirelessly charge.  These mergers are definitely a start in the right direction, but there is still plenty of work to be done in those areas.


Future Uses of Wireless Charging Technology

Wireless charging has yet to become standard, but it is constantly improving as more companies begin to integrate the technology into their devices. For example Samsung and several Android makers have already begun to integrate the technology into their devices, and iPhone is rumored to be working on wireless charging integration as well. Places like Ikea and Starbucks have also started introducing wireless charging pads into their facilities.
Wwireless Charging Technology in the Future

Nonetheless, wireless charging technology is reaching a crossroad. It is no longer just about placing a smartphone on a pad – we need to think about the next generation of devices.  It may take some time, but wireless charging is unquestionably on the horizon. So next time you hear about wireless charging, think of your future devices, be it wearables or IoT devices that will seamlessly or wirelessly charged in charging stations part of your everyday environment – no strings attached.


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