Engineers at Tufts University have developed new methods to more efficiently fabricate materials that behave in unusual ways when interacting with microwave energy, with potential implications for telecommunications, GPS, radar, mobile devices, and medical devices. The innovation, described in Nature Electronics, constructs the metamaterials using low-cost inkjet printing, making the method widely accessible and scalable, while also providing benefits such as the ability to be applied to large conformable surfaces or interface with a biological environment. It is also the first demonstration that organic polymers can be used to electrically "tune" the properties of the metamaterials.
Electromagnetic metamaterials and meta-surfaces — their two-dimensional counterparts — are composite structures that interact with electromagnetic waves in peculiar ways. The materials are composed of tiny structures — smaller than the wavelengths of the energy they influence — carefully arranged in repeating patterns. The ordered structures display unique wave interaction capabilities that enable the design of unconventional mirrors, lenses and filters able to either block, enhance, reflect, transmit, or bend waves beyond the possibilities offered by conventional materials.
Tufts engineers fabricated their metamaterials by using conducting polymers as a substrate, then inkjet printing specific patterns of electrodes to create microwave resonators. The printed devices can be electrically tuned to adjust the range of frequencies that the modulators can filter.
Metamaterial devices operating in the microwave spectrum could have widespread applications to telecommunications, GPS, radar, and mobile devices, where metamaterials can significantly boost their signal sensitivity and transmission power. The metamaterials produced in the study could also be applied to medical device communications because the biocompatible nature of the thin film organic polymer could enable the incorporation of enzyme-coupled sensors, while its inherent flexibility could permit devices to be fashioned into conformable surfaces appropriate for use on or in the body.