Design of Dual-Band Bandpass Filter for Effective Filtering in a Next-Generation Handheld Wireless Devices

This paper presents the design and characterization of a dual-band bandpass filter (BPF) that utilizes multiple open and short-circuit stubs. The filter's center frequency and bandwidth of both passbands can be adjusted by controlling the length and width of the stubs. The proposed BPF operates at two center frequencies of 2.4 and 6.2 GHz, respectively. The proposed design yields five transmission poles and zeros in two passbands with fractional bandwidths (FBW) of 40% and 24.6%, respectively. The filter's minimum insertion loss is 0.5 dB, and the maximum return loss is 13.9 dB. Moreover, the proposed BPF design offers a remarkable out-of-band suppression of 37.8 dB in the upper stopband region of 6 GHz, making it ideal for various wireless communication applications. To validate the filter's response, a prototype has been fabricated, and the measured and full-wave electromagnetic simulation results are well-matched.