AbstractA new scheme with an interdigital line and a defected ground structure for dual‐band operation is dealt with in this letter. The proposed structure is analyzed using a series L‐C resonator model added a parasitic shunt capacitance. The nonlinear phase of this structure is dependent on the dumbbell size of the defected ground. This proposed scheme is applicable for a short‐ended stub circuit and a dual pass‐band filter at the centre frequencies of 860 and 1810 MHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1353–1356, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24331