Development of dual-band microstrip bandpass filter based on split ring resonator

Abstract

An approach to develop a dual-band microstrip bandpass filter (BPF) is proposed based on split ring resonator (SRR) structure. The reason of using SRR structure is due to its advantages such as having strong coupling connection between its loops and workable as lumped LC series. The proposed BPF is designed on a grounded 1.9mm thick high relative permittivity Roger RT/Duroid® 6010 dielectric substrate with the dimension of 25mm × 20mm. Prior hardware realization, some parametric studies are carried out by varying the gap of rings as well as the separation between rings. From the characterization, it shows that the realized SRR-based dual-band microstrip BPF prototype has the first-band center frequency of 0.99GHz with −3dB working bandwidth of 47.8MHz and the second-band center frequency of 1.99GHz with −3dB working bandwidth of 134MHz. In spite of the measured results have slightly differences with the simulated one especially for the second frequency band, in most cases the characteristics of realized prototype have good agreements with the design ones.