Communication systems often rely on multiband tunable antennas. Traditionally, Micro-Electro-Mechanical Systems (MEMS) or diodes are used during the tuning process. As systems move to higher frequencies in the trek toward 5G, the conventional adjustment process falls short.
Researchers at the University of Bristol have tuned operation frequency and radiation patterns by utilizing optically induced plasmas in silicon. This method could expand the operational efficiency and overall performance of next-gen communication networks and radar systems.
Two papers outline the research. The process of tuning radiation patterns by placing an optically induced superstrate plasma over microstrip antennas is published in The Institute of Engineering and Technology (IET) Optoelectronics. The journal IEEE Transactions on Antennas and Propagation details an optically tunable cavity-backed slot antenna that can meet emerging communication standards.
“This technology relies on the interaction between light and a semiconductor such as silicon. When the semiconductor is illuminated by an appropriate wavelength of light, the photons generate electrons and holes which increase the conductivity in the silicon creating a ‘metal-like’ region,” says Martin Cryan, professor of Applied Electromagnetics and Photonics at the University of Bristol. “Microwave signals can then interact with these conductive regions and with correct design, tunable antennas and circuits can be created.”
MEMS switches and diodes rely on complex DC Biasing circuits. However, the new approach requires no physical connection to the silicon, according to Cryan. This can increase design simplicity when multiple antenna elements are necessary.
The team plans to continue improving current technology, setting their sights on high power levels and millimeter wave frequencies.
