You know what a cantenna is right? It's a 2.4 GHz waveguide made out of a can (like a big soup can or juice can). It's directional, so you have to aim it. Usually they are mounted outside to achieve very long distance links between another node with a similar antenna that are lined up. In other words it's not something you would lug around with you inside of your house.
However you could put in on your WAP / Wireless Router to get coverage in a specific direction.
Dan East