I am a student and am wondering if you could help me. This is NOT a homework
assignment to begin with. I am not looking for detailed answers but how would
you approach a task like this? This is a possible PhD project and I would like
some feedback on the pros and cons of such a topic.

The International Technology Roadmap for Semiconductors (ITRS) predicts 9nm
linewidth processes by 2016, making it then possible to build complex electronic
systems of the order of microns in size. The same roadmap predicts that whilst
process linewidth scales by a factor of approximately five the wirebonded I/O
pads will only shrink by a factor of two, showing the difficulty in making these
connections. Further the transistors that drive these pads will take up
significant area on the IC. Such systems may not be purely electronic; so-called
smart dust and microrobots might have sensors, micromechanical (MEMS) elements,
biomolecules, and use electronics as an interface to a biological sensor. In all
cases communicating with these systems is a formidable challenge.

Wireless communications, if possible, has several advantages over the normal
wired connections that are used to supply power and transmit information to and
from electronic systems and integrated circuits. For micron order machines the
lack of interface area, the energy required and the physical difficulty in
making a wired connection are replaced by the problem of integrating a single
transceiver.

Implementing wireless communications is not straightforward however. For antenna
operation with reasonable directivity and therefore energy efficiency the
antenna should be many wavelengths across. Radio communications is particularly
inefficient, as the antenna sizes are extremely small fractions of the emission
wavelength.

Optical wavelengths are more promising. Transmit and receive antennas that can
operate efficiently can be built on scales of tens of microns, and efficient use
can be made of received radiation in silicon detectors or phototransistors.
There is still the problem of integrating a compact high-efficiency source of
radiation however.

Modulated retro-reflectors allow communications systems where one terminal (the
machine) does not require a source. Such a retro-reflector, together with the
silicon microelectronics and liquid crystal layers to allow data modulation can
create a micro-machine that can be used to sense, and act on external
information.

The key problems are to;

(i) Provide reliable communications between these machines and the external
world

(ii) Ascertain the locations of the machines, so that their sensor information
can be correlated with position.

(iii) Ensure that sufficient energy is available to power the communications
process

Thanks and sorry to bother you.





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