I came across one commercial manufacturer by chance - looked very interesting to start with, but reading through the specs it quickly became clear that, like most things to do with propagation, there is no such thing as a free [rf] lunch!
While the antenna did indeed offer substantial size advantages for its bandwidth (it was an impressive bandwidth - and only one model was avaliable) there were significant comprimises when it came to perrformance across the entire bandwidth Gain suffered, there were big changes to radiation pattern across the bandwidth, front/back ratio wasn't too impressive, return loss was to good.... etc etc .......
Another observation: it's one thing designing an antenna along these lines to cover, say 20Ghz if the lower freq is say 1Ghz - that would be relatively easy to do. Now try designing a 20Ghz bandwidth antenna which starts at or below 1Mhz! Things are now very different
In short: antennas of this sort will be very application specific and will need to be designed with a defined application in mind to get the best out of them. Research is ongoing just like it is with respect to paint-on/spray-on antennas (yes - antenna in spray can - it exists commercialy! - but performance is nowhere like a conventional antenna, though acceptable). One possible application (like spray-on antennas) is covert application i.e. been able to design an antenna that looks nothing at all like an antenna and takes up next to no space/volume. In that respect there are commercial antennas that are woven into clothing so the shirt or jacket is the antenna
...... and then there is cost: won't be cheap - how much? Off the top of my head it wouldn't suprize me if something like the atricle refers to comes out costing in excess of a $1000 - that is a guess, but i just can't see the design/time equation working out to anything less.
Antennas like this, avaliable off-the-shelf for day to day use?
Nope, not at the moment, but it'll come to pass sometime over the next decade or so.
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