Optimizing Dual Wideband Microstrip Bandpass Filters: A Genetic Algorithm Approach with Transmission Line Modelling

This paper provides a framework for an intelligent design methodology for a dual-band bandpass filter (DB-BPF), utilising a modified genetic algorithm (GA) approach for enhanced efficiency and accuracy over traditional GA techniques. In this design, the electrical parameters optimized using a variation of conventional GA. To expedite and refine the optimisation process, a transmission line model is employed to compute the fitness values during the GA process. For demonstrating the utility of the method, a dual-band bandpass filter with frequencies 2.2 GHz and 5 GHz (fractional bandwidth 63.6% and 36% respectively achieved) has been designed. The optimized design is confirmed using full-wave methods such as the Method of Moments (MoM) and electromagnetic (EM) simulation via CST software. The prototype circuit size of the dual-band bandpass filter is only about 0.34λg × 0.20λg. The predicted and simulated results verify the effectiveness of the proposed method, demonstrating high efficiency and superior in-band and out-of-band performance.