Tri-band bandpass filter with wide stop-band using stub-loaded triple-mode resonator

摘要: A novel microstrip tri-band bandpass filter (BPF) based on stub-loaded triple-mode resonator is proposed. The open- and short-circuited stubs are asymmetrically loaded to a uniform impedance open-loop resonator, constructing resonator. Benefiting from the proposed asymmetrical loading scheme, designed BPF not only possesses controllable bandwidths of three passbands, but also shows very wide stopband. Finally, with good performance at 1.5, 2.57, 3.83 GHz. Three transmission zeros near passbands obtained improve selectivity BPF. Meanwhile, other produced in stopband enhance harmonic suppression level. rejection level 4.3 13.7 GHz better than 20 dB. measured results agreement simulated data.