Microstrip bandpass filters using asymmetrical tapered-line resonators for improved stopband characteristics

This paper proposes new microstrip bandpass Alters using modified linear tapered-line resonators (LTR) which are asymmetrical structures for improving stopband performances. The design concept is based on step impedance resonator by adjusting width on one side of the linear tapered-line resonator to be asymmetrical structure. These filters provide wider upper stopbands resulting from resonator bandstop characteristics. The simulated and experimental results of stopband performances are better than 15 dB for a frequency range up to 5f_0.