A group of engineers has solved an electromagnetism mystery, which may lead to the development of incredibly small antennas. The ‘last frontier’ of semiconductor design could have huge implications for the telecommunications industry and the Internet of Things.
In a report published in the journal Physical Review Letters, University of Cambridge engineers suggest electromagnetic waves can also be generated by a phenomenon called symmetry breaking.
How antennas function
Antennas work by launching energy into free space via electromagnetic or radio waves. Additionally, they also serve to collect energy. However, engineers have yet to figure out a viable solution for making antennas smaller and compatible with electronic circuits.
“Antennas, or aerials, are one of the limiting factors when trying to make smaller and smaller systems, since below a certain size, the losses become too great,” said engineering professor Gehan Amaratunga. “An aerial’s size is determined by the wavelength associated with the transmission frequency of the application, and in most cases it’s a matter of finding a compromise between aerial size and the characteristics required for that application.”
In addition to size, another issue with antennas is the mysteries associated with them. For instance, the researchers point out that a clearly-explained mathematical model of a practical aerial does not exist. In fact, 19th Century scientist James Clerk Maxwell has provided the bulk of what is known regarding electromagnetic radiation.
Understanding electromagnetic waves
“In dielectric aerials, the medium has high permittivity, meaning that the velocity of the radio wave decreases as it enters the medium,” said lead author Dhiraj Sinha. “What hasn’t been known is how the dielectric medium results in emission of electromagnetic waves. This mystery has puzzled scientists and engineers for more than 60 years.”
The engineers used thin films of piezoelectric materials (an insulator that deforms once voltage is applied) and discovered that a certain frequency caused the materials to become efficient radiators. According to the researchers, these materials can serve as aerials.
The team concluded that symmetry breaking is connected to this phenomenon. Symmetry of the electronic field is achieved when electronic charges are motionless. “In aerials, the symmetry of the electric field is broken ‘explicitly’ which leads to a pattern of electric field lines radiating out from a transmitter, such as a two wire system in which the parallel geometry is ‘broken’,” explained Sinha.
Implications for the Internet of Things
Amaratunga added: “If you want to use these materials to transmit energy, you have to break the symmetry as well as have accelerating electrons – this is the missing piece of the puzzle of electromagnetic theory,” said Amaratunga. “I’m not suggesting we’ve come up with some grand unified theory, but these results will aid understanding of how electromagnetism and quantum mechanics cross over and join up. It opens up a whole set of possibilities to explore.”
In addition to the telecommunications industry, Amaratunga`s research could have implications for the Internet of Things (the idea that almost everything in homes and offices can be connected to the internernet).
Amaratunga says Piezoelectric materials – which can be made using lithium niobate, gallium nitride and gallium arsenide – are easy to create. “It’s actually a very simple thing, when you boil it down,” said Sinha. “We’ve achieved a real application breakthrough, having gained an understanding of how these devices work.”
Source: University of Cambridge