On Wireless Power Spatial Freedom


Emerging technology is subject to skepticism and scrutiny, and wireless power is no different. As engineers and product developers, it’s crucial to absorb these critiques with the aim of advancing the technology’s performance. The Why Wireless Charging is Here to Stay series examines the prevailing critiques of wireless charging. To kick-off, we discussed wireless power transfer capabilities and speed. This time, we’re tackling spatial freedom limitations. 

“Spatial Freedom of Wireless Technology is Substantially Limited”

Although wireless power has been around for over a century, many consumers hadn’t experienced it until smartphone manufacturers began integrating it into devices in the mid-2010s. The Wireless Power Consortium created a standard for inductive technology, called Qi (pronounced: chee), that would emerge as the wireless power transfer method of choice for phones. 

Before Qi, most consumers were tethered to a one-meter-long cord if they wanted a charge, setting the bar relatively low on user experience. The first Qi-enabled smartphones were revolutionary in their ability to be charged by simply being placed on the correct spot on a charging surface. 

But why would the phones need to be placed “correctly” on a wireless charger? What did “correct placement” even mean?  Shouldn’t we be able to set it and forget it? 

Spatial freedom refers to how precisely a device needs to be placed on its charging surface to receive a charge, and it’s an important consideration in wireless charging. With an initial separation distance of 3-5mm between transmitter and receiver, Qi’s limited range impacted performance, user experience and new product development.

NuCurrent however, saw the potential to advance the Qi standard and sought to expand the separation distance (spatial freedom) and speed, thereby improving performance, enhancing user experience, and opening up more products to the Qi standard. 

Enter: MP-A17, a design specification that triples the separation distance of standard Qi charging to 12mm, and can deliver up to 15W of continuous power. In many ways, MP-A17 gives Qi a second chance, especially to early adopters that were unimpressed with the initial wireless charging experience. With MP-A17, Qi users don’t have to remove their phone cases or grips; or worry about having consistent, precise alignment to charge quickly and reliably. What’s more, is that MP-A17 brings extended range Qi charging to new places and spaces like in RVs, boats, cars, furniture and more. 

What Other Options are There? 

Qi prevailed in the smartphone segment over other technologies… but what about the other product categories well-suited for wireless power that need increased spatial freedom? 

One alternative to Inductive Charging is Inductive Resonant Charging, a related technology that also uses magnetic fields (inductance) to transfer power, but at a higher operating frequency of 6.78MHz (versus Qi’s 110-210 KHz operating frequency). 

Inductive Resonance provides greater spatial freedom, multi-device charging on a single transmitter and higher power ranges up to 300W, making it an attractive option for products ranging from implantable medical devices to drones or autonomous inventory robots. 

Another available technology is Radio Frequency (RF) wireless power transfer. RF wireless power uses the same technology that’s traditionally been used to transfer communications in applications such as BlueTooth and WiFi. In this instance however, the challenge is in harnessing the total power of a radio frequency that may be beamed across a room, house or even further. 

While well-funded companies like Energous and Ossia are leading the charge in this developing space, product managers must know that RF wireless powered devices have yet to make an appearance in the mass market. Due to the extremely low power levels (microwatts – milliwatts), RF could be an option for “trickle charged” devices such as sensors, IoT and LED Lighting in the future. 

Watch this Space 

With seven wireless power transfer methods available today, there is not a one-size-fits-all transfer method created for any and all products. However, it’s clear that innovation and technological progress are being made across the industry. The AirFuel Alliance and Wireless Power Consortium are continuing to update their specifications in an effort to advance the standards, while improving power levels, spatial freedom and user experience. Meanwhile, players like Apple and Samsung are prioritizing their own ecosystems with proprietary wireless chargers. Either way, consumers shouldn’t be quick to cancel wireless power, it’s here to stay.