retically possible, but years away due to the
time and cooperation involved in real standards
Qi technology is undoubtedly the leader in
number of mobile devices deployed worldwide.
Apple, Google, HTC, LG, Motorola,
Nokia, and Samsung have launched Qi mobile
phones (note: Google added Qi for Nexus 4,
but dropped it from future models citing “slow
charging times” that must be addressed before
they include it again). Likewise, infrastructure
adoption is unparalleled with Qi included in
over 35 automotive models, IKEA furniture, Corian
countertops, and standalone Qi transmitters
of different shapes, colours, and sizes (to
name only a few…).
AirFuel adoption is limited mostly to pilot scale.
Dell launched a laptop in 2017; LG launched
a limited-edition phone; and a variety of infrastructure
deployments and accessories have
pilot deployments in hotels, sports venues,
airports, and coffee shops around Asia, Europe,
and the U.S.
Proprietary NFMC has surprising levels of deployment,
partially owed to the fact that certain
niches have been using wireless power since
the 90s. For example, implanted neurostimulators,
electronic toothbrushes, and industrial
equipment interconnects have been employing
magnetic-coupling technology for over two
decades. Granted, the
technology has evolved
to be much smaller,
faster, and more userfriendly
today, but millions
of products have
been shipping annually
using proprietary nearfield
since the early 2000s.
RF has no major commercial
has been impressively
displayed by a variety of
demos where multiple
phones are charged
simultaneously at distances
Figure 1. NuCurrent’s high-efficiency wireless power solutions are frequency
independent and frequency-compliant across the Wireless Power
Consortium (Qi) and AirFuel Alliance.
up to 15 feet away from the source.
Most companies developing RF technology are
in the pre-regulatory phase of development or
have created off-shoot products that utilize RF
technology, but at distances substantially lesser
than the ultimate promise of RF.
Ultrasound is in the earliest stage of all. Limited
demos have been provided, but no commercial
products are available. The few demos offered
are similar to RF demos in that they appear to
slowly charge cell phones at distances of a few
metres away from the source. The development
efforts seem to be early stage and potentially
still confronting fundamental challenges.
The main value of Qi is that it’s interoperable
and going to be everywhere. The main limitation
of Qi is the use case. Qi relies on tightly
coupled technology, low frequency, and limited
in-band communication. For users, this means
that device separation is limited to 3-5 mm,
flexibility is limited, and the promise of simultaneous
charging and data-transfer rate depends
on an external data protocol.
There are workarounds for most of the limitations.
For example, multiple-source power
27 DesignNews NOVEMBER 2017 www.eedesignnewseurope.com