A pan European collaboration, involving researchers from Romania, Greece, Italy, and Ireland, has demonstrated a graphene antenna that operates in the spectrum and which can be tuned using an external voltage.
The antenna, developed using graphene from Graphenea, is less than 1mm thick and has a planar diameter of 100mm, which the team says makes it one of the smallest microwave antennas in the world.
Using a simple fabrication procedure and a standard CVD graphene layer on an SoI substrate, the team says it has shown antenna efficiency and its operating frequency in the X band can be modulated by applying a voltage.
In the microwave part of the spectrum, researchers have been looking for an antenna material which can be tuned with an external voltage. While advances have been made using exotic ferroelectrics, ferromagnetics and liquid crystals, these materials exhibited strong losses, preventing the creation of efficient microwave antennae.
With graphene, electrons can oscillate quickly with little loss, due to the peculiar relativistic behaviour of charge carriers in graphene. This enables the creation of transistors that operate at frequencies up to several terahertz.
The research also shows the antenna can radiate in two directions, which could be useful or detrimental, depending on the application. Directionality can be controlled with a thin reflector layer on the rear of the antenna.
The main application for this antenna will be in RF communications, where the antenna tunability will allow switching of communication channels. However, the antenna could also serve as an RF sensor.