Taking control of electromagnetic waves

Research lives: Dr Conor Brennan, associate professor, Dublin City University School of Electronic Engineering

Dr Conor Brennan, associate professor, Dublin City University School of Electronic Engineering.

Dr Conor Brennan, associate professor, Dublin City University School of Electronic Engineering.


The research in your lab looks to control electromagnetic radiation. That sounds ambitious, can you explain?

“Electromagnetic or EM radiation exists along a spectrum and includes lots of kinds of energy, from light to infra-red to radio waves to microwaves. It enables much of the technology used in the modern world, from telecommunications to medical imaging. In all these technologies, we need to understand and control how EM waves get from A to B, and my research explores better ways of controlling how these waves move around, and through, objects and materials.

How do you do that?

We do a lot of mathematical simulations or modelling. It’s relatively easy to write down the equations for how EM waves interact with materials and to approximately solve these equations. But it gets really hard to solve them to the high levels of accuracy needed to allow telecommunications networks handle more and more data, or to achieve better resolution in medical imaging technology. However, once you can solve the equations, you can do all sorts of interesting things, like design metamaterials to help control the path taken by EM waves.


Yes, it’s a great word, it refers to artificial materials that we precisely engineer to behave in unusual ways to do things that would not occur naturally.

Can you give us an example?

One science-fiction-like example would be an invisibility cloak, like in Harry Potter. We see things because light bounces off them, but if you wrapped an object in a material that could guide light from behind the object around it, then the light re-joins in front of the object and hits your eye. You would not see the object but would instead see what is behind it. It sounds far-fetched but people are getting closer to it, albeit under laboratory conditions.

Ta-dah! But you are not making things disappear, what’s your ‘metamaterial goal’?

We are looking at new ways to make metamaterials that can absorb and guide EM waves of the kind used in telecommunications networks. One of the researchers in my lab, Dr Patrick Bradley, has been 3D printing non-metallic materials that contain water in various carefully designed shapes. The idea is that the water absorbs and guides the waves in interesting ways. This kind of approach will hopefully pave the way for cheap and precisely structured metamaterials that let you control where EM waves go. This can lead to smaller, more compact, antennas, for example.

What’s the best part of your work?

I’m originally a pure mathematician and I still get a kick seeing how fundamental maths can be applied to so many different areas. I also love working with the researchers in my lab. It’s very humbling to work with such talented students and young colleagues. They can build and do things I can’t do, and I am honoured to be able to help them develop as researchers.

How do you take a break and get some headspace?

I like to play music, and I write and record with my wife, under the name ‘Molasha’, which comes from Molaise, a 7th-century Carlow saint – it’s a long story. Thanks to Garageband, I have the level of production capabilities that Paul McCartney had in ’60s and ’70s, although that is sadly where the similarity ends!”