Highly omnidirectional and frequency tunable multilayer graphene-based monopole patch antennas

We report a facile approach for producing highly omnidirectional and frequency tunable antennas based on multilayer graphene/multi-walled carbon nanotube (MG/MWNTs) electrodes. The MG sheets are obtained by ball milling graphite, followed by sonication. Monopole patch antennas are prepared by screen printing the MG/MWNTs paste onto a polymer substrate. The resulting antennas show excellent performance due to the bridge effect of the MWNTs between well-dispersed adjacent MG layers, which increases the contact area between MG sheets along the horizontal and vertical axes. The antennas formed from the MG/MWNTs exhibit smaller return losses than the antennas formed from pristine graphite, as well as high radiation efficiency (∼44.9%). Moreover, the MG/MWNTs antennas require a relatively small quantity, which leads to low production costs. In addition, the dimensions of the antennas can be simply adjusted by controlling the screen printing mask or cutting with scissors to achieve frequency tunability. These results demonstrate the potential of these MG/MWNTs antennas for applications in wireless communications for ubiquitous sensor networks. Highly omnidirectional and frequency tunable antennas based on multilayer graphene/multi-walled carbon nanotube electrodes were produced by a facile fabrication method.