An article by two Birmingham academics from the Department of Electronic, Electrical and Systems Engineering has been recognised by the editors of the IOP Science Journal of Optics as a Highlight of 2015.

Broadband near-zero index metamaterials by Dr Konstantinos Konstantinidis and Dr Alexandros Feresidis was acknowledged for its high novelty, scientific impact and broad appeal.

Metamaterials are complex artificial structures that are specially designed and engineered to produce electromagnetic properties that are not readily available in nature. A class of metamaterials are those that exhibit an effective refractive index with values close to zero, which is a property that cannot be found in any conventional material. The article presents a new way of designing and realising near-zero index metamaterials with increased bandwidth. The design is based on multiple periodic metallic surfaces stacked on top of each other and has low fabrication complexity. The proposed metamaterial is employed to produce broadband directive emission from a single low-directivity source and the performance is demonstrated experimentally at microwave frequencies.

Dr Alexandros Feresidis said,

“This research paves the way for the realisation of near-zero index metamaterials with increased bandwidth performance. This is particularly important for a large number of envisaged applications for these materials, where the near-zero index properties must be obtained over a wide bandwidth.”  

“The development of the proposed broadband metamaterials helps their applicability in practical components such as new broadband antennas for telecommunications and radar systems, or even more futuristic applications such as invisibility cloaks!”

The next generation of broadband wireless networks will require high performance broadband antennas operating at frequencies much higher than existing systems; this research will have a direct impact on the development of high performance telecommunication and radar systems. Research is ongoing to implement the proposed designs at higher microwave and terahertz frequencies.

All 2015 Highlights feature in a special online collection freely available here.