Morphing Meta-antennas enable frequency manipulation

An antenna’s physical properties are inextricably linked to its electromagnetic properties and how it radiates and receives radio waves. One of the simplest examples is extension, like with an old cell phone or FM radio antenna. But shape and structure can have more dramatic effects, which is why we have so many different kinds of antennas. If you could change the shape of an antenna on demand, you could influence the frequencies it transmits, receives, and resonates. An MIT CSAIL-led research team developed morphing Meta-antennas that take advantage of that for many useful applications.

These Meta-antennas are made by laser-cutting a sandwich composite of dielectric material surrounded by conductive material, in patterns that allow for manual stretching, flexing, folding, and squeezing.

In the most basic implementation, a Meta-antenna form affects its optimal transmission frequency. Imagine if you had a device that transmitted on both 433MHz and 2.4GHz, depending on function. That device could have a single meta-antenna, which the user quickly morphs to suit the transmission frequency in use. 

But this technology is much more interesting when you consider its passive use cases. You could, for instance, put a Meta-antenna on a door. The act of opening the door affects the shape of the antenna and therefore its transmission frequency properties, which is easily detectable by a receiver. That could even work through resonance with a separate transceiver and could enable more sophisticated sensing, almost like an RFID chip and sensor combined into one low-cost unit — one with much better range.

The Meta-antenna team tested the designs in different situations using an Arduino UNO Rev3 board, connected to a vector network analyzer to collect data. That wasn’t really necessary to prove the concept — the physics here are well-known and aren’t controversial in the least — but it is nice to see visualizations of transmission and resonance data.

Best of all, the Meta-antennas would be very easy for anyone to make with affordable tools and materials. That stands out when compared to technology like RFID chips, which require massive investment to produce. 

Image credit: M. AlAlawi et al.