Tri-band RF filters optimization using evolutionary strategy

This paper presents a tri-band RF filter based on T-shape resonators, whose dimensions are determined using evolutionary strategy. The T-shape resonator input impedance has three resonance frequencies with two transmission zeros for improving its passbands isolation. In order to validate the proposed approach, a filter with three poles and center frequencies at 0.75, 1.5 and 2.25 GHz had been designed and numerically evaluated by using the electromagnetic Designer and HFSS from ANSYS. Resonator impedances and lengths are determined by the optimization process performed by a proper adapted evolutionary strategy, which is a computational intelligence approach with biological inspirations from the parents and offsprings relations.