An evolved S-band helical antenna with 1.8G bandwidth

Differential evolution (DE) is applied to optimize S-band helical antenna in this paper. The helical antenna spires on a paraboloid which is formed by revolving a parabola curve, not as usual as on the surface of a cylinder. And the spaces between two turns are changeable, not usually constant. In this way, the search space for the helical antenna is increased. This helical antenna design is then formulated into a constrained optimization problem (COP). The coefficients of the parabola curve and the spaces between turns are search variables. The design requirements are modeled into objective and constraints. An evolved antenna meets the requirements. It has a wider frequency band and higher gains than the referred one in this paper.