Wide stopband ultra-wideband suspended stripline filter

A novel ultra-wideband(UWB) bandpass filter(BPF) is proposed based on suspended stripline, using the substrate RT/Duroid 5880(lossy) with a thickness of 0.254 mm, dielectric constant of 2.2 and loss tangent of 0.0009,in this letter. Possessing of the characteristics of high Q-value, low loss and slightly influence from the temperature, the suspended stripline structure, which composed by two broadside coupled capacitive-loaded transmission line resonators with a narrow gap in the upper layer and two stepped impedance short stub in the lower layer, is put forward to get a high performance, that is the remote spurious passband, well harmonic suppression behavior, perfect inset and return loss and sharp skirt in the sideband. All of those good characteristics are shown from the simulation results in the end.