A novel dual-band bandpass filter using asymmetric stub-loaded stepped-impedance resonators

This paper presents a novel microstrip dual-band bandpass filter using asymmetric coupled stub-loaded stepped-impedance resonators (SLSIRs) at frequencies of 1 and 2.6 GHz. Each resonator is first designed and simulated to operate at the given frequencies. Then, they are coupled together while applying suitable coupling configurations at the input and output to improve the filter´s performance. The filter´s input reflection coefficients (S₁₁) are -11.2 and -12.9 dB and insertion loss (S₂₁) are -0.44 and -1.2 dB at the two design frequencies respectively. Numerical simulations are performed in the full-wave EM and circuit simulator ADS, which have verified the design concept.