Excitation of surface wave on circular-loop array

A method is presented of analyzing surface-wave excitation to an infinite periodic linear array in which only one element is excited and all others are parasitic. The approach taken in the analysis is based on the properties of the periodic structure. A formal solution for the current distribution on the array element is obtained, and the propagation constant of the surface wave is also found. In the case where the array consists of loop antennas, the surface wave can propagate only when the separation of the array element is less than one-half wavelength and the circumference of the loop is less than one wavelength. Calculated values of the propagation constant of an array are in good agreement with the measured results.