It's happened to all of us. You're in the
middle of an intense conversation, and your cell phone cuts out. Even today,
in the era of 4G and smartphones, it's still difficult to completely avoid the
most basic failure of a cell phone -- a
Enterprising researchers at the University of Illinois have
devised an antenna that uses a revolutionary 100 µm micro-nozzle silver
nanoink printing process to print an antenna on a 3D substrate to try to remedy
that problem [press
As a demo, they printed nanoink on the outside or
exterior of a hollow hemisphere of glass. This wasn't easy to do.
States Jennifer T. Bernhard [profile],
the computer and electrical engineering professor leading the project,
"Unlike planar substrates, the surface normal is constantly changing on
curvilinear surfaces, which presents added fabrication challenges. To our
knowledge, this is the first demonstration of 3D printed antennas on
Current phone antennas perform relatively poorly,
because many are shorter than their operating wavelength. And some are poorer
than others (like the first
hardware version iPhone 4). Designing a 3D antenna has been the goal
of several research projects. Describes Professor Bernhard, "Recent
attention has been directed toward producing antennas by screen-printing,
inkjet printing, and liquid metal-filled microfluidics in simple motifs, such
as dipoles and loops."
But she feels that her design is the best attempt
at creating a 3D antenna yet. She states, "Omnidirectional printing
of metallic nanoparticle inks offers an attractive alternative for meeting the
demanding form factors of 3D electrically small antennas (ESAs)."
She says that the antenna they printed and tested
was near "perfect" from a reception perspective. She writes,
"There has been a long-standing problem of minimizing the ratio of energy
stored to energy radiated—the Q—of an ESA. By printing directly on the
hemispherical substrate, we have a highly versatile single-mode antenna with a
Q that very closely approaches the fundamental limit dictated by physics (known
as the Chu limit)."
By adjusting the space of the meandering lines and
the total antenna cross section, the 3D antenna design can be tuned to a
particular operating frequency.
The antenna design could have many applications,
as the ink can be printed on a variety of substrates and surfaces -- not just
hollow hemispheres. States Professor Bernhard, "This conformal
printing technique can be extended other potential applications, including
flexible, implantable, and wearable antennas, electronics, and sensors."
Antennas could potentially be printed on the
inside of cell phone cases, inside the cases of laptops, or on the wings of
military unmanned aerial vehicles (UAVs) -- offering long desired super-low Q
antennas for these applications.
A paper on the work, entitled "Conformal
Printing of Electrically Small Antennas on Three-Dimensional Surfaces" [abstract]
has been published in the March 18 edition of the peer-reviewed journal of
If the antenna is everything that is claimed,
hopefully mass production of the printing process can be worked out, as the
material required -- silver nanoink -- is relatively cheap and available.
If the printing nozzle/equipment can be pushed out at an affordable cost,
your smart phone in a couple years could get a 3D antenna and better reception.
Of course this will only help to eliminate the
number of problems on the phone side. Cell phone networks can
have uncovered patches and cell phone towers can be overloaded in cases of high
use. Having a fancy antenna will most definitely not help
you with those kinds of problems.