The Challenge
As part of the SpaRK research project, Plextek designed, simulated and fabricated a number of metamaterial surfaces. We also investigated the use of metamaterials for the propagation of RF energy via surface waves.
The Approach
Surface waves are known to propagate along thick dielectric substrates – the dielectric acts as a surface waveguide or transmission line. A key characteristic of surface waves is the exponential decay of the electric and magnetic fields normal to the surface. In other words, RF fields are tightly bound to the surface.
Metamaterials are artificial materials that exhibit unusual electromagnetic properties not found in naturally occurring materials. Metamaterial surfaces – also termed metasurfaces – are generally formed using periodic metallic structures on top of a dielectric substrate, which results in enhanced surface waveguide characteristics compared to the dielectric-only substrate.
These metamaterial surfaces can also be exploited to create low-profile antennas that have wider operational bandwidths than conventional antennas above a conducting surface. Metasurfaces can also be modulated in order to control antenna radiation patterns; for example, to create directional beams
In summary, metamaterial surfaces and structures offer exciting opportunities for novel antenna designs using techniques encompassed by the field of transformational electromagnetics.
The Approach
Surface waves are known to propagate along thick dielectric substrates – the dielectric acts as a surface waveguide or transmission line. A key characteristic of surface waves is the exponential decay of the electric and magnetic fields normal to the surface. In other words, RF fields are tightly bound to the surface.
Metamaterials are artificial materials that exhibit unusual electromagnetic properties not found in naturally occurring materials. Metamaterial surfaces – also termed metasurfaces – are generally formed using periodic metallic structures on top of a dielectric substrate, which results in enhanced surface waveguide characteristics compared to the dielectric-only substrate.
These metamaterial surfaces can also be exploited to create low-profile antennas that have wider operational bandwidths than conventional antennas above a conducting surface. Metasurfaces can also be modulated in order to control antenna radiation patterns; for example, to create directional beams
In summary, metamaterial surfaces and structures offer exciting opportunities for novel antenna designs using techniques encompassed by the field of transformational electromagnetics.
The Outcome
Measurements showed excellent agreement with simulations and proved the effectiveness of these metamaterial surfaces for surface-wave transmission of RF energy.
Plextek were one of the winners of the 2016 SpaRk (Small-to-Medium-sized Enterprise Partnerships Advancing Raytheon Knowledge) Competition.
