Application of Trapezoidal-Shaped Characteristic Basis Functions to Arrays of Electrically Interconnected Antenna Elements

This paper describes a novel technique for generating the characteristic basis functions (CBFs) used to represent the surface currents on finite arrays of electrically interconnected antenna elements. The CBFs are high-level basis functions, defined on subdomains in which the original problem is divided. They are initially generated on extended subdomains; next, an easy-to-implement windowing technique is applied to them to truncate the undesired singularities in the currents generated at the artificial edges of the subdomains. The envelope of the window is trapezoidal in shape and we deliberately introduce a certain amount of overlap between the supports of the CBFs to ensure the continuity of the currents across the common interface between the adjacent subdomains. The accuracy and effectiveness of this method is demonstrated for a moderate as well as a large size array of tapered slot antennas (TSAs).