A dual-band bandpass filter with novel resonators arrangement

In this paper, by using novel arrangements of two microstrip resonators, a dual-band bandpass filter is presented. By placing a couple of open-circuited stubs to the corner points of a hexangular loop resonator, the resonator structures have been formed. By means of moving gaps between the open-circuited stubs to obtain a perturbation effect, two mode frequencies and transmission zero points emerged. By using two resonators, this filter has two different passbands. Although there are two resonators, only have one feed-line. This means the two resonators share the same feed-lines. By arrange one resonator into the other, designed dual-band bandpass microstrip filters have a compact size of 12mm × 10.39mm surface area and such a configuration has been satisfied a compact structure. Several figures are demonstrated to show the simulation results.