surface wave and travelling wave antennas

what is mean by surface wave,another one what is the mechanism of travelling wave antenna i know it loaded by matched load?

Most antennas work by resonance. In transmission line speak, this comes from setting up a standing wave. However, if there is no reflected wave, then we create a travelling wave antenna. Typically there are two ways to do this: 1.) have a matched load 2.) have a long antenna which radiates all its energy before it's reflected.

Surface waves are guided waves that propagate along an interface. They are tightly bound to the interface, i.e., the decay exponentially as one moves away from the interface. A microstrip p@tch antenna loses energy to surface waves that propagate along the air-dielectric interface.