Joint optimisation of ground, feed shapes with material distributive topology of patch in UWB antennas using improved binary particle swarm optimisation

Abstract

A joint optimisation of the ground plane and feed structure shapes, and the topology of radiating patch in ultra wideband (UWB) antennas are proposed. The material distributive topology of the radiating patch is configured with symmetric and asymmetric topologies. The ground plane and feed structure of antenna are optimised from a set of discrete feasible combinations. The ground plane, feed structure and radiating patch topology are identified based on the particle's position vector of the improved binary particle swarm optimisation algorithm. Based on this vector, the antenna is simulated and tested by using the MATLAB–Computer Simulation Technology (CST) co-simulation method. The fitness value of the each particle is calculated from the return loss value evaluated by the CST and the particle's velocity and position vectors are accordingly updated. Compared to asymmetric topology, the symmetric topology antenna converges faster because of reduced search space dimension. The symmetric topology UWB antenna is further miniaturised to occupy an area of from based on the observation of surface current distribution. The measurement results of the fabricated prototypes confirm that all the three antennas yield good impedance matching over the UWB band with better pulse preserving capability.