Electromagnetic wave propagation over non-uniform surface impedance planes

The EM wave propagation over and radiation from nonuniform surface impedance planes are studied by numerical methods using integral formulations of the compensation theorem. The surface impedance is assumed to be a known factor and to only vary in the direction of propagation. These integral formulations are particularly used to investigate surface wave antennas, finite length sinusoidally modulated reactance surfaces (SMRS), and groundwave propagation. The radiation characteristics of the surface wave antenna such as directivity, beam width, and side lobe level are discussed. Radiation from the finite length SMRS is investigated for various parameters which characterize the surface reactance, such as modulation amplitude, period, length of modulated section, and average surface reactance. The approximate radiation pattern is obtained analytically, and compares well with the radiation pattern found numerically.