In this article, a new balanced wideband bandpass filter (BPF) is designed using a stub-loaded multimode resonator (SLMMR) with tightly coupled feeding lines. The wideband response is achieved by designing the first three differential resonant modes of the SLMMR to locate evenly in the designated passband. Good common-mode (CM) suppression over the passband is obtained by positioning the transmission zero produced by one half of the low-impedance section (which serves as a shunt open-circuited stub while the BPF is in CM operation) of the SLMMR close to the in-band common modes. A prototype of the proposed BPF is fabricated and measured; the measured (simulated) minimum differential-mode insertion loss (IL) is 0.7 (0.3) dB and the measured (simulated) CM IL is greater than 20.3 (20.1) dB in 1-10 GHz.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering