Leaky waves: basic properties and applications

This presentation will describe the basic properties of leaky waves and how they play an essential role in a variety of different applications. It will begin by explaining why leaky waves are physical even though they are mathematically improper, and will then discuss such topics as the basic principles underlying the operation and design of leaky-wave antennas, show how purely guided (bound) modes on printed-circuit transmission lines become leaky at higher frequencies and how such leakage produces crosstalk and other harmful effects in microwave and millimeter-wave integrated circuits, and then describe the properties of spectral gaps that occur at the transition between bound and leaky modes, where the guided-mode solution becomes nonphysical over a small frequency range. Finally, if time permits, it will be shown how leaky waves serve to explain several basic and interesting physical phenomena, such as Cerenkov radiation and the high efficiency of optical surface-wave prism and grating couplers.