Compact tri-band bandpass filter with controllable frequencies

摘要

In this paper, we present a compact tri-band bandpass filter (BPF). The resonator, which consists of a main transmission line, a center-loaded open stub and a side-loaded open stub, is utilized to obtain the three resonance frequencies. After selecting the impedance of each stub at this resonator, the passband frequencies can be controlled individually. Four transmission zeros are generated to enhance the selectivity. For demonstration, a compact tri-band BPF is implemented. Good agreement between the measured and simulated results is presented to verify the theoretical predication. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:573-577, 2016