This article presents the design of a compact fourth-order cross-coupled dual-band bandpass filter (BPF) having a wide upper-end stopband. Quarter-wavelength (λ/4) stepped-impedance resonators (SIRs) were employed to construct the BPF to have a relatively small circuit size and high spurious harmonics, as compared with the BPF using half-wavelength (λ/2) SIRs. The resonators tapped by the input and output feeding lines were loaded by a spur-line to suppress the first spurious passband so as to further broaden the upper-end stopband. BPFs with and without the embedded spur-lines were both simulated to compare their frequency responses. Very good agreement between the simulated and measured results was observed.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering