A team of physicists from the University of Namur in Belgium have discovered that graphene serves as an effective shield against microwave inference. Graphene has the ability to reduce microwave pollution and to enhance the electromagnetic compatibility of future electronic devices.
Philippe Lambin, project lead, and and his colleagues demonstrated that “the conductivity of several graphene layers adds arithmetically when thin polymer spacers separate them. Maximum microwave absorption in the Ka communications band between 26.5 and 40 GHz is achieved with six graphene planes separated by layers of poly-methyl methacrylate (PMMA), a transparent plastic also known as acrylic glass.”
The process of creating these multilayer sheets begins with a layer of graphene on a copper foil substrate. A 600-800 nanometer PMMA spacer is then put on top of the graphene layer. Ferric chloride is then use to etch away the copper and the structure is transferred to a quartz substrate. This procedure is repeated until the number of layers desired is achieved.
The team’s experiments demonstrated graphene can absorb up to 25 percent of microwave radiation, and with a multilayer graphene/PMMA arrangement, it can absorb up to 50 percent.
Researchers also noted that the interface between the shielding material and air is important to study.
“We have found that the static conductivity of graphene is close to the value which relates the magnetic and electric fields in any electromagnetic radiation propagating in air. Thanks to this happy coincidence, graphene is an ideal material for absorbing radio waves, thus protecting sensitive electronic devices,” Lambin said.
