| Popis: |
This paper presents a compact mixed coupled quarter-wavelength $(\lambda/4)$ resonator filter employing J/K inverters and coupling-path phases. In contrast to conventional mixed coupled models, the proposed method makes use of separated J and K inverters to obtain desired electric and magnetic couplings respectively. A transmission zero (TZ) below passband is created by applying capacitive dominant mixed coupling between $\lambda$/4 uniform impedance resonators (UIRs). In addition to coupling magnitude, the TZ also depends on coupling path phases. Tapped feed lines implied between resonators and input-output (I/O) ports provide necessary electrical length ratio between J and K coupling paths. A fourth order prototype filter at 10GHZ with 6.8% fractional bandwidth (FBW) is designed, fabricated and tested. The measured results show good agreement with simulated response, which verifies the design approach. |
