Compact bandpass filter structure using an open stub quarter-wavelength microstrip line corrections

In this paper, bandpass filter development with the assistance of the Richards-Kuroda transformation method, on the basis of the known Chebyschev-lowpass filter, is presented in Matthaie, et al. (1980). A new compact microstrip bandpass filter using a quarter-wavelength λ-transmission line resonator is proposed by Hong and Lancaster (2001).The suggested filter consists of four coupled microstrip lines, two are shorted to the ground by an inductive microstrip line, and the other two are coupled together by means of a J-immitance inverter by Bachtold, et al. (1999). Changing the long open stub, the center frequency shifts to the left or to right within the frequency range. Two-pole-Chebyschev bandpass filter is fabricated, and tested at 4.55GHz.