DR ALEXANDER W. POWELL. RESEARCH Fellow, UNIVERSITY OF EXETER
Dr Alex Powell is a research fellow at the Centre for Metamaterials Research and Innovation at the University of Exeter.
His research is focused on improved antenna design through advanced magnetic structures, and taking electromagnetic metamaterials into the third dimension, both in terms of their design, and fabrication through the use of advanced manufacturing methods.
He is currently exploring a variety of complex structures, both to understand the fundamental physics governing their behaviour, and to apply this understanding to tackle real world problems such as improving antenna directivity, designing tuneable reflectarrays for telecommunications, and increasing the radar visibility of small objects such as drones.
He has recently been awarded a fellowship from the Royal Society of Engineering to develop novel structures to control the interaction of microwaves with small objects.
Presentation Synopsis:
“Metamaterials for compact antennas and increased radar visibility’’
Metamaterials can be defined as “materials engineered to have properties not found in nature” and over the last two decades researchers at Exeter and beyond have engineered exotic structures such as flat lenses, negative index materials and “invisibility cloaks”. One advantage of metamaterials is the ability to minimise the size of devices like antennas, whilst maintaining or enhancing their capabilitites. Structures that are almost 2D can be used to control the emission or scattering of electromagnetic radiation without necessitating dramatic alteration beyond the surface of an object.
My research focusses on the miniaturisation of antennas, both through the use of of Artificial Magnetic Conductors and though exploring directivity via magnetic instead of electric coupling between passive and driven elements. I am also interested in designing brightly, or highly directionally scattering structures in order to make small objects more visible to radar. These could take the form both of resonant particles, or planar arrays where a passive phase modulation between elements ensures that light is always retroreflected in the direction it came from, significantly enhancing the Radar Cross section. Through recent innovations in roll-to-roll manufacturing, it is possible to make these elements transparent to visible light, enabling integration on top of solar panels.
The Centre for Metamaterials Research and Innovation (CMRI) at the University of Exeter is a world leading institute for metamaterials research, with a long history of successful collaboration with industrial partners. I am very intestersted in ways in which we could collaborate with SMEs and larger companies in the space sector in order to improve satellite technology, and would welcome further discussion. “