Design and analysis of widely separated Dual-mode Dual-Passband filter

In this paper, A new miniaturized Dual-mode, Dual-Passband filter using modified multi-mode resonator and coupled feed lines is proposed. In the proposed structure, coupled feed line is used not only to feed MMR, but also to generate stopband between two passband. Later, widening of this stopband is achieved as a result from loose coupling of feed lines and length of MMR. To construct two passband with centre frequency at 4.5GHz and 9GHz, Series and parallel resonance characteristics of MMR is used. Further, MMR is modified to yield good passband performance. The characteristic of the dual-band filter in terms of bandwidth, passband and out of band responses are controlled by the impedances of stub (MMR) and the odd- and even-mode impedances of the coupled line. The length, width and spacing of MMR and coupled lines in the proposed design are wisely chosen to produce the desired frequency response. The proposed filter demonstrated dual passband 4GHz-5GHz and 8.2GHz-9.6GHz, with a wide stopband 6GHz-7.5GHz. The proposed filter is to be designed using substrate material R03010 with relative dielectric constant of 10.2 and thickness of .762mm.