Improved theoretical and experimental models for the coaxial colinear antenna

An improved theoretical model of the coaxial colinear (COCO) antenna is presented that takes into account different element lengths and power transfers between the antenna and the transmission lines. The antenna equation now contains an exact kernel instead of an approximate kernel and a piecewise constant basis function is used instead of a piecewise linear function, yielding faster results. More points are used for better accuracy and yet faster computations. The linear systems of equations of the theoretical model are solved using a preconditioned conjugate gradient method. Uniform and tapered current distributions are obtained experimentally and theoretically on end-fed coaxial colinear antennas. There is reasonable agreement between theory and measurements. The gains of a few COCO antennas relative to equivalent lengths of half-wave dipoles are given