Ultra wideband antenna design using discrete Green's functions in conjunction with binary particle swarm optimisation

The binary particle swarm optimisation (BPSO) in conjunction with the time-domain discrete Green's function (DGF) method is proposed for designing of printed ultra wideband (UWB) antennas. In the DGF method, on one hand, a three-dimensional problem is reduced to a two-dimensional one, and on the other hand, the broadband frequency characteristics of the antenna are achieved with a single simulation run. Furthermore, the spatial discrete representation of the current on the antenna, in the DGF method, facilitates implementation of its combination with the BPSO algorithm. Two different UWB antennas are designed using the proposed approach. First, an antenna is designed to minimise voltage standing wave ratio (VSWR). The experimental result shows that the antenna has a VSWR about <1.5 over the UWB range. Second, an antenna is designed to have not only low VSWR, but also stable radiation pattern over the UWB range. The experimental results show a good impedance matching and stable omnidirectional pattern over the UWB range.