so ive been wondering this for a while and just had a chance to ask. when it comes to microwave radiation in the ~2.4ghz range. why is it that microwaves such as in a microwave oven or microwave communication towers they use hollow waveguides to channel the signal and the same wavelength in the same frequency range can be channeled through wires such as the antenna in a 802.11g wireless access point?

 

Waveguides can handle more power with lower losses.