AbstractIn this article, a second‐order dual‐band bandpass filter is designed. The filter consists of two dual‐band resonators connected by a dual‐band admittance inverter. The dual‐band resonator unit is made of two shunt stubs that coordinately produce two resonances. A novel dual‐band quarter‐wavelength line acts as the admittance inverter, providing suitable admittance transformations. To verify the design concept, a filter working at 2 and 5 GHz is devised and fabricated on Rogers' RO3006 printed circuit boards. In addition, the dual‐band filter is connected with a bandstop filter to suppress the unwanted spurious response. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1184–1187, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23326