I came across this company, Fractal Antenna Systems today in the RFID related info-stream. Fractal antennas are both smaller and more powerful than conventional antennas, and well suited for embedded systems like medical devices. Fractal antennas have two basic advantages, they are equally effective over a wide frequency range (conventional antennas' length determines the frequency for which they're most effective) and they don't need adjustment with electronic components, which makes them simpler and smaller. According to this brief history:
up his short wave radio system in his flat in central Boston. The lease stipulated no
antennae on the outside of the building, so he had to be inventive. He
had read Mandelbrots fractal book and got the idea to try out a fractal
antenna. He cut out aluminium foil in the form of an inverse Koch curve
and glued it to a piece of A4 paper. It worked amazingly well. Not
until later did he realize how innovative he had been. In the time that
followed he tested the antenna properties for other fractals, with good
results, and then he founded Fractal Antenna Systems in 1995.
Science has yet to fully understand why
fractals work so well as antennae, but there is progress. In 1999 in
the magazine Fractal
Robert Hohlfeld and Nathan Cohen proved that for an antenna, to work
well for all frequencies, it has to be symmetrical and self-similar.
Over time Fractal Antenna Systems has built up an apparently robust competitive barrier through a number of patents.
Fractal Antenna Systems currently sells and licenses antennas for a variety of demanding applications. Although there is no mention of implantable or patient worn medical devices, this seems to be an obvious application.
Pictured right is a fractal antenna.