The Research and Design of 5.5 GHz Bandpass Filter for WLAN

Based on analyzing the characteristics of coupled microstrip lines, a design of RF microstrip bandpass filter for WLAN is studied. This paper presents on bandpass filter operating at center frequency of 5.5GHz with 1GHz bandwidth. The results of full-wave electromagnetic simulation indicate that the filter shows a very good performance with insertion loss below 1.458dB and return loss better than -16.294dB in its passband and stopband attenuation of less than -42.459dB.The group delay in the midband frequency drops to 1.168ns, which further improves the quality of transmission signals.