Design of dual band band-pass filter using defected ground structure

A dual band band-pass filter using ring resonator and defected ground structure is presented in this paper. In design, a ring resonator is used to generate two pass bands, and two defected ground structures help to realize high impedance microstrip lines, which make the control process of the two pass band frequencies convenient. To verify the design, a dual band band-pass filter is simulated and fabricated at 2.45GHz and 3.55GHz. Measured results and simulated results show the frequency spacing of the two pass bands could be adjusted conveniently by changing the dimension of defected ground structure.