Shape-changing antenna enables more versatile sensing and wide-range communication

MIT researchers have developed a reconfigurable antenna that dynamically adjusts its frequency vary by altering its bodily form, making it extra versatile for communications and sensing than static antennas.

A consumer can stretch, bend, or compress the antenna to make reversible adjustments to its radiation properties, enabling a tool to function in a wider frequency vary with out the necessity for advanced, transferring components. With an adjustable frequency vary, a reconfigurable antenna might adapt to altering environmental situations and scale back the necessity for a number of antennas.

The phrase “antenna” could draw to thoughts metallic rods just like the “bunny ears” on prime of previous tv units, however the MIT crew as an alternative labored with metamaterials—engineered supplies whose mechanical properties, equivalent to stiffness and power, rely upon the geometric association of the fabric’s parts.

The result’s a simplified design for a reconfigurable antenna that could possibly be used for purposes like vitality switch in wearable gadgets, movement monitoring and sensing for augmented actuality, or wi-fi communication throughout a variety of community protocols.

As well as, the researchers developed an modifying instrument so customers can generate custom-made metamaterial antennas, which might be fabricated utilizing a laser cutter.

“Normally, after we consider antennas, we consider static antennas—they’re fabricated to have particular properties and that’s it. Nonetheless, through the use of auxetic metamaterials, which might deform into three totally different geometric states, we will seamlessly change the properties of the antenna by altering its geometry, with out fabricating a brand new construction.

“As well as, we will use adjustments within the antenna’s radio frequency properties, on account of adjustments within the metamaterial geometry, as a brand new methodology of sensing for interplay design,” says lead writer Marwa AlAlawi, a mechanical engineering graduate scholar at MIT.

Her co-authors embrace Regina Zheng and Katherine Yan, each MIT undergraduate college students; Ticha Sethapakdi, an MIT graduate scholar in electrical engineering and laptop science; Soo Yeon Ahn of the Gwangju Institute of Science and Expertise in Korea; and co-senior authors Junyi Zhu, assistant professor on the College of Michigan; and Stefanie Mueller, the TIBCO Profession Growth Affiliate Professor in MIT’s departments of Electrical Engineering and Laptop Science and Mechanical Engineering and chief of the Human-Laptop Interplay Group on the Laptop Science and Synthetic Intelligence Lab.

The research can be introduced on the ACM Symposium on Consumer Interface Software program and Expertise (UIST 2025), held in Busan, Korea, September 28–October 1.

Making sense of antennas

Whereas conventional antennas radiate and obtain radio alerts, on this work, the researchers checked out how the gadgets can act as sensors. The crew’s aim was to develop a mechanical aspect that may also be used as an antenna for sensing.

To do that, they leveraged the antenna’s “resonance frequency,” which is the frequency at which the antenna is best.

An antenna’s resonance frequency will shift on account of adjustments in its form. (Take into consideration extending the left “bunny ear” to scale back TV static.) Researchers can seize these shifts for sensing. As an example, a reconfigurable antenna could possibly be used on this approach to detect the growth of an individual’s chest, to observe their respiration.

To design a flexible reconfigurable antenna, the researchers used metamaterials. These engineered supplies, which might be programmed to undertake totally different shapes, are composed of a periodic association of unit cells that may be rotated, compressed, stretched, or bent.

By deforming the metamaterial construction, one can shift the antenna’s resonance frequency.

“To be able to set off adjustments in resonance frequency, we both want to alter the antenna’s efficient size or introduce slits and holes into it. Metamaterials permit us to get these totally different states from just one construction,” AlAlawi says.

The gadget, dubbed the meta-antenna, consists of a dielectric layer of fabric sandwiched between two conductive layers.

To manufacture a meta-antenna, the researchers lower the dielectric laser out of a rubber sheet with a laser cutter. Then they added a patch on prime of the dielectric layer utilizing conductive spray paint, making a resonating “patch antenna.”

However they discovered that even essentially the most versatile conductive materials could not stand up to the quantity of deformation the antenna would expertise.

“We did plenty of trial and error to find out that, if we coat the construction with versatile acrylic paint, it protects the hinges so they do not break prematurely,” AlAlawi explains.

A way for makers

With the fabrication downside solved, the researchers constructed a instrument that allows customers to design and produce metamaterial antennas for particular purposes.

The consumer can outline the dimensions of the antenna patch, select a thickness for the dielectric layer, and set the size to width ratio of the metamaterial unit cells. Then the system routinely simulates the antenna’s resonance frequency vary.

“The great thing about metamaterials is that, as a result of it’s an interconnected system of linkages, the geometric construction permits us to scale back the complexity of a mechanical system,” AlAlawi says.

Utilizing the design instrument, the researchers included meta-antennas into a number of sensible gadgets, together with a curtain that dynamically adjusts family lighting and headphones that seamlessly transition between noise-canceling and clear modes.

For the sensible headphones, as an example, when the meta-antenna expands and bends, it shifts the resonance frequency by 2.6%, which switches the headphone mode. The crew’s experiments additionally confirmed that meta-antenna buildings are sturdy sufficient to resist greater than 10,000 compressions.

As a result of the antenna patch might be patterned onto any floor, it could possibly be used with extra advanced buildings. As an example, the antenna could possibly be included into sensible textiles that carry out noninvasive biomedical sensing or temperature monitoring.

Sooner or later, the researchers need to design three-dimensional meta-antennas for a wider vary of purposes. Additionally they need to add extra capabilities to the design instrument, enhance the sturdiness and adaptability of the metamaterial construction, experiment with totally different symmetric metamaterial patterns, and streamline some handbook fabrication steps.

This story is republished courtesy of MIT Information (web.mit.edu/newsoffice/), a preferred web site that covers information about MIT analysis, innovation and educating.