3D printing method advances electrically small antenna design

Now, researchers at the University of Illinois have demonstrated, for the first time, 3d printed antennas on curvilinear surfaces. According to Jennifer Bernhard, a Professor of electrical and computer engineering at Illinois, these antennas are electrically small relative to a wavelength (typically one twelfth of a wavelength or less) and exhibit performance metrics that are an order of magnitude better than those realised by monopole antenna designs. "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," she said. "However, these fabrication techniques are limited in both spatial resolution and dimensionality, yielding planar antennas that occupy a large area relative to the achieved performance. Prof Bernhard went on to explain how omnidirectional printing of metallic nanoparticle inks offers an attractive alternative for meeting the demanding form factors of 3d electrically small antennas (ESAs). "To our knowledge, this is the first demonstration of 3d printed antennas on curvilinear surfaces. There has been a long standing problem of minimising the ratio of energy stored to energy radiated - the Q - of an ESA," she stated. "But by printing directly on the hemispherical substrate, we created a highly versatile single mode antenna with a Q that very closely approaches the fundamental limit dictated by physics (known as the Chu limit)." According to the researchers, their design can be rapidly adapted to new specifications, including other operating frequencies, device sizes, or encapsulated designs that offer enhanced mechanical robustness. "This conformal printing technique can be extended to other potential applications, including flexible, implantable and wearable antennas, electronics, and sensors," Prof Bernhard concluded. The research findings and fabrication methods are being featured in the 18 March issue of Advanced Materials.