Analysis and design of nano-antennas (nantennas) for energy harvesting


50000403v1689

Promoter: Guy Vandenbosch

details
Description: In recent years there has been a phenomenal growth of the research on nanostructures. It is becoming more and more obvious that nano-technologies will form a pillar on which future technological leadership will be based.
One major field in this global quest for smaller and smaller structures is nano-photonics. Nano photonics is studying the ways to manipulate visible (wavelength from 400 to 700 nanometer) and infrared light using very small artificial structures (size of the order of a wavelength). The large interest in this field is motivated by the availability of a lot of (currently underutilized) energy in the visible and IR range, hence energy harvesting is a large research driver for this. The interaction between light and these structures can still be analyzed with a high degree of accuracy using classical electromagnetic theory. It means that the concept of an “antenna”, a device able to transmit and receive electromagnetic waves rather than particles, still works. The study of nantennas as such has emerged very recently. The expectations are high but many claims for nantennas in reality still have to be thoroughly investigated and shown in practice:
- highly efficient and cheap energy harvesting from solar radiation and even body radiation in the optical and infrared spectrum, where a theoretical efficiency as high as 92 % has been predicted, compared to a value of about 20 % for solar cells,
- passive, energy-neutral cooling by converting infrared radiation into radiation that is not felt as heat, and vice versa, passive heating,
- extremely efficient lighting by basically broadcasting photons from the nantennas,
- infrared and multi spectral imaging, near field optical microscopy, chemical and biological sensing, single molecule spectroscopy, and high density optical storage
Although the basic working mechanism of a nantenna is the same as for a classical antenna, the practical analysis and design shows considerable differences. The challenges tackled in this Ph.D. are the following.
Since the frequency is orders of magnitude higher, the characteristics of the materials used may be very different from those at microwave frequencies. This has to be taken into account in the modeling of the nantenna. Classical antenna tools in the microwave range work with substrates with very low losses and with an almost constant permittivity. This is not the case for nantennas, where the losses may be high, and the variation of the parameters with frequency may be enormous. Due to the higher losses and present day fabrication technologies, nantennas have to be described with 3D volume currents, rather than with currents flowing at the surface (of a volume). This requires considerably more computer resources if not properly handled.
The first goal of the Ph.D. is to tackle all these problems. The second goal is to make appropriate nantenna designs for solar energy harvesting.

Key words: antenna, energy harvesting

Latest application date: 2010-04-30

Financing: available

Type of Position: scholarship

Duration of the Project : 4 years

Research group: Department of Electrical Engineering (ESAT)

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