AbstractA new type of dumbbell‐shaped defected ground structure (DGS) is introduced in this article. Its dual‐bandgap characteristics are reported for the first time and can be adjusted by changing the dimension of complementary split‐ring resonators (CSRR) unit and gap. The dual bandstop filter using proposed DGS is designed and fabricated. Measured results show that there are two bandgaps centered at 3.35 GHz and 5.82 GHz, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2908–2910, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24776