Optimal Design of Zig-Zag Antenna Using Nonlinear Segment Length and Pitch Angle

Zig-zag antennas are preferred in VHF applications. In conventional Zig-zag antenna structure the important parameters are pitch angle(α),and segment length of Zig-Zag elements. The vertex angle and segment length are constant for a conventional uniform Zig-Zag antenna. This paper proposes a methodology for optimal design of Zig-Zag antenna with nonlinear segment length and varying vertex angle for maximizing gain with circular polarization. Segment length and pitch angle of the antenna are parametrically modeled using B-Splines. Optimization is done using particle swarm optimisation(PSO) and antenna parameters are estimated using Numerical Electromagnetic Code(NEC2). The C++ source code of NEC2 software is suitably modified to incorporate spline modeling and PSO. Numerical simulation results shows that the antenna modeled by proposed method gives better gain characteristics compared to antenna with constant length and vertex angle.