Thursday, September 12, 2013

CST interviews Dr Miguel Beruete, Universidad Pública de Navarra

Beruete’s group: (left to right) Victor Pacheco, Bakhtiyar Orazbayev,
Victor Torres, Miguel Beruete, and Unai Beaskoetxea.
How are metamaterial devices simulated? That’s what we asked Dr. Miguel Beruete from Universidad Pública de Navarra. He won CST University Publication Awards in 2005 and 2012, and is active in metamaterials and plasmonics.

CST: Thanks for speaking to us, Miguel. Both of your University Publication award wins have been for work with metamaterials – once in 2005 for frequency selective surfaces, and in 2012 for a metamaterial lens. What role has simulation with CST MICROWAVE STUDIO® played in developing metamaterials?
Beruete: Well, it can be said that CST MICROWAVE STUDIO was fundamental in both of them. I would say that this is general in most of the research carried out in our group. Usually, we come up with ideas for new devices or applications, or simply, performances that we want to test. Our estimations, which at this stage are quite rough and mostly driven by intuition, are then confronted with CST MICROWAVE STUDIO which gives us a very realistic view of the validity of them. As I said before, this is usually a necessary step before doing the experimental work. Also, when we do purely analytical calculations, such as equivalent circuit analysis of metamaterials, we check our predictions with calculations done using the software.

CST: Is this what the group did in the award winning papers?
Beruete: In fact, the papers that won University Publication awards are good examples. In the one of 2005, we analyzed and characterized experimentally metasurfaces made with Split-Ring Resonators (SRRs) and Complementary Split-Ring Resonators (CSRRs). At that point, the CSRR was a new metamaterial particle, and it seemed interesting to evaluate its performance in the context of metamaterials in planar technology. In the paper, experimental results were compared with the numerical simulations that, of course, had been obtained in advance.
In the paper that won in 2012, we evaluate several metamaterial lenses done using a stacked hole arrays. Here, we used CST from the very beginning up to the end and employed several of the simulation packages available in the software: first, we fixed the dimensions and operation frequency of our stacked hole arrays from the dispersion diagram obtained using the eigenmode solver. With this information we could obtain the shape of our lens analytically. Next, we simulated its performance in the time domain and checked it experimentally. In this particular case, the study was somewhat more involved, since we found experimentally a second peak of enhancement that we had overlooked in the simulation. So, we had to come back to our workstations to analyze again the lens at this second peak, to find finally that it was due to an epsilon-near-zero metamaterial operation.

CST: Metamaterials are currently a hot topic of research, and are also starting to find industrial applications. What developments do you see for the field in the near future?
Beruete: This is probably the million dollar question, so to say. In my opinion, it is likely that some of the metamaterial applications that have been suggested during the last years will be finally unfeasible, at least in the short term. Nevertheless, there are currently some interesting technological advances in the miniaturization of planar microwave circuits, improvement of antenna radiation and so on. Nowadays, there is a trend towards mixing metamaterials and plasmonics and applying metamaterials ideas from microwaves to higher frequency ranges such as THz, infrared, etc. These ideas seem very promising for microscopy, sensing, optical circuits and for a variety of applications in biology, medicine, security, defense, and so on.
Metamaterials in general have served to revisit old and apparently well-established concepts, shading new light on them. They have been the playground where physicists and engineers have worked together and this has produced a very fast development of new ideas and applications. If only for this, research on metamaterials have been definitely fruitful.

CST: You’ve won the CST University Publication Award twice now. Has the award helped you and your group in carrying out research?
Beruete: These awards have been very helpful for us! They have increased our international visibility. CST is well-known worldwide for anyone doing research in electromagnetism and for us, this distinction is extremely beneficial for showing our work. Of course, the upgraded license helps us in continuing with our research lines.

CST: Is there any other work you’re currently involved in that you would like to highlight?
Beruete: Nowadays we are exploring several research lines in our group. We continue with our work on metamaterials and extraordinary transmission structures. We are doing an effort to increase our operation frequency to THz and infrared, to merge metamaterials and plasmonics. We are opening new research lines such as nanoantennas for sensing applications. In all our research, we always put a special care into developing practical applications, so we are constantly applying the knowledge we get from fundamental investigation towards practical devices such as lenses, frequency selective surfaces, polarizing devices, beam steerers, etc. Thus, we will definitely use CST for our future research!

CST: That’s always great to hear! Thanks for taking the time to chat to us.

For more information, see Miguel Bereute’s homepage and LinkedIn profile.

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