Design of quadrifilar helical and spiral antennas in the presence of satellite-mobile handsets using genetic algorithms

Two circularly-polarised quadrifilar helical and spiral antennas, operated at 1.6 GHz and intended for the applications of satellite mobile communications, were designed using genetic algorithms. The antennas were firstly considered as a test on an infinite ground plane and then optimised further on small size handsets. The performance of the optimised antenna designs was analysed using commercial simulators in terms of VSWR, axial ratio and power gain. The attained results indicate that the optimal antennas met design objectives under several certain constraints. Moreover, the capabilities of GA are shown as an efficient optimisation tool for selecting globally optimal parameters to be used in simulations with an electromagnetic antenna design code, seeking convergence to designated specifications.