Antennas of flexible nanotube films an alternative for electronics

Science Daily  June 10, 2019 Early work on carbon nanotube (CNT) antennas indicated that their performance could not match that of metals such as copper. However, recent improvements in fluid phase CNT processing have yielded macroscopic CNT materials with better alignment and conductivity. A team of researchers in the US (Rice University, NIST) conducted radiation efficiency measurements of microstrip patch antennas made of shear-aligned CNT films measuring radiation efficiency of 94% at 10 GHz and 14 GHz, matching equivalent copper antennas. The minimum CNT film thickness required to match the performance of copper drops with increasing frequency due to reduced losses […]

SLAC develops novel compact antenna for communicating where radios fail

Science Daily  April 12, 2019 The highest radiation efficiency antennas require size at the scale of the wavelength (here, >1 km), making portable transmitters extremely challenging. A team of researchers in the US (SLAC National Accelerator Laboratory, industry, SRI International) used a rod-shaped crystal of a piezoelectric material, lithium niobate, as their antenna. When they applied an oscillating electric voltage to the rod it vibrated, alternately shrinking and expanding, and this mechanical stress triggered an oscillating electric current whose electromagnetic energy then got emitted as VLF radiation. Switching the wavelength during operation allowed them to transmit with a large bandwidth achieving […]

Shape-shifting origami could help antenna systems adapt on the fly

Tech Explore   December 10, 2018 Researchers at the Georgia Institute of Technology focused on Miura-Ori, which has the ability to expand and contract like an accordion, to create radio frequency filters that have adjustable dimensions, enabling the devices to change which signals they block throughout a large range of frequencies. They used a special printer that scored paper to allow a sheet to be folded in the origami pattern. An inkjet-type printer was then used to apply lines of silver ink across those perforations, forming the dipole elements that gave the object its radio frequency filtering ability. They found that […]