CPW band-pass filters using centrally-loaded resonators

Abstract

Coplanar-waveguide (CPW) Band-pass filters using novel Centrally-loaded Resonators (CLRs) have been proposed in this report. The advantages offered by the CLRs include suppressing the even-mode resonant frequencies as well as tuning the even-mode resonant frequencies to achieve dual-band operation, without altering the fundamental resonant frequencies. The planar CPW structure also eased the fabrication process and was ideal for shunt and series connection. To design CPW Band-pass filters with CLRs, the characteristics of CLRs were first studied by theoretical analysis and full-wave simulation using electromagnetic simulator HFSS. Prototype single-pass-band filters were then developed to achieve 5% and 10% relative bandwidth. After that, CLRs were adopted to design a single-pass-band filter with suppressed second harmonic. Finally, dual-band filters were constructed using CLRs with both lumped and distributed elements. In total, five CPW Band-pass filters have been successfully simulated and fabricated. The measured results coincided with the data generated from simulation.