Radiation from modulated surface wave structures - I

A \´modulated\´ surface wave is one whose phase and/or amplitude varies as the wave propagates along a surface. Structures that support such a wave are characterized by an effective index of refraction that varies in the direction of propagation. Pattern calculations based on harmonic analysis of the spatial frequencies contained in phase- and/or amplitude-modulated waves show that surface wave antennas can be built (a) with very high endfire gain (for example, Simon\´s "cigar" antenna, which inspired this work), (b) with the beam tilted at an arbitrary angle with the surface. Preliminary experimental evidence has been obtained.