Article ID: 14.20170022
In this paper, a new design method of the dual-band bandpass filter which consists of feed line with stepped-impedance resonator (SIR) structure, open-loop ring resonator (OLRR) with SIR, and uniform OLRR is proposed. The SIR structure which can control harmonic frequencies is used to provide the maximum magnetic coupling at the same positions of both the upper and lower feed lines, irrespective of the first passband and the second passband of the dual-band bandpass filter and improve characteristic of stopband between the first and second passbands. This proposed design method was confirmed to be useful from measured results for dual-band bandpass filter operated at 2.4 GHz and 5.5 GHz.
