A Modified Particle Swarm Optimizer and its Application to the Design of Microwave Filters

In this paper, a modified particle swarm optimization (PSO) algorithm is presented and its applicability is shown for the design of specific microwave filter as a case study of microwave components. In the proposed modified PSO algorithm, particles in the swarm are divided to form multiple sub-swarms. The social component of PSO’s velocity update equation is modified to include the effects of multiple sub-swarms. Five benchmark functions have been considered for testing the proposed algorithm. The approach has been tested for two basic modifications of PSO namely PSO with inertia weight (IW) and PSO with constriction factor method (CFM). The simulated results illustrate that the modified PSO algorithm has the potential to converge faster, thus reducing the computational expenses, while maintaining/improving the quality of solution. Finally, the proposed algorithm is used for the design of coupled microstrip line band pass filter which is a computationally expensive process when the design is conducted using evolutionary algorithms and electromagnetic (EM) simulation tools.