I'm starting to research building a multi-band antenna in the 1.9 gigahertz range. I see them offered on wireless routers, and they use them in cellular sites. Can anyone provide a reference or quick explanation of how they are constructed? Or, is it hype altogether, and the antennae are really only cut for one frequency, but the other frequencies have mediocre SWR?
In the HF band, I've build and used trap dipoles that are multi-band, but I have the feeling that in the SHF range there may be a better/different approach.