This paper presents a dual-band bandpass filter composed of λ/2 and λ/4 stepped impedance resonators (SIRs) for the WLAN applications. The filter covers both the operating frequencies of 2.45 and 5.2 GHz. The doubly parallel-coupling mechanism is used in the filter design to provide alternative routes for signals of distinct frequencies. The tapped-line I/O feed is adopted in this circuit to create the attenuation poles for improving the signal selectivity and stopband rejection levels. Experiments are conducted to verify the circuit performance.