This Antenna Won’t Get Bent Out of Shape

For short-range wireless communications, electronic devices have very small antennas that are commonly built right into the PCB itself. But for longer-range communications, the solution lies somewhere between a dipole antenna and a satellite dish. With cords being cut left and right due to the emergence of ever more wireless options with higher bandwidth and lower latency, the proliferation of antennas is likely to accelerate. If we want to avoid sticking ugly antennas in every available free space, we will need to rethink antenna design.

A group at MIT has been thinking about this issue, and they have put forward a potential solution. They have developed a soft and flexible shape-changing antenna that can be incorporated into everyday objects, like curtains or furniture. It is inexpensive to produce, and the frequency that these antennas transmit or receive can be altered by simply giving it a squeeze or stretch — something like changing the length of a rabbit ear antenna. The rapid reconfigurability also has another advantage: it enables the material to act as a sensor.

The team refers to their creation as the Meta-antenna, and it works by embedding antennas within metamaterials. These are engineered structures whose properties depend on geometry rather than just composition. Unlike static antennas, which are locked to a specific frequency and performance profile, the Meta-antenna can be reconfigured mechanically. A simple bend, compression, or rotation shifts the device’s resonance frequency.

The Meta-antenna consists of a dielectric substrate sandwiched between two conductive layers, forming a patch antenna. It was made using a metamaterial called auxetic kirigami, which is a patterned structure that expands, contracts, and rotates in programmable ways. As the metamaterial deforms, the antenna’s physical geometry changes, directly altering its radio-frequency behavior. Because no motors, actuators, or bulky mechanical assemblies are required, the design is lightweight and robust.

Since the antenna’s resonance frequency shifts with deformation, the structure itself can be used as a sensor. As such, a Meta-antenna could be integrated into clothing, for instance, that monitors breathing by detecting chest expansion, or furniture that measures strain and stress through frequency changes. This dual role, communication and sensing, is a significant step forward compared to conventional static antenna designs.

The team demonstrated a few prototypes that highlight the material’s potential as a sensing system. In one demonstration, a curtain was produced that dynamically adjusts the lighting level in a home depending on how far open or closed it is. They also developed a pair of headphones that can switch between noise-cancelling and transparent modes as the user physically adjusts them.

To make it simpler to create devices of this sort, the researchers developed a design tool that allows users to generate custom metamaterial antennas. By setting parameters like patch size, dielectric thickness, and cell dimensions, users can automatically simulate the resulting frequency range. From there, fabrication can be as straightforward as laser-cutting rubber sheets and applying conductive spray paint.

Looking ahead, the researchers plan to explore three-dimensional versions of the Meta-antenna, expand the range of supported deformation patterns, and streamline the fabrication process. They also hope to deploy the technology into smart textiles, adaptive personal electronics, and interactive home systems for real-world applications.