Investigation of coupling structures for coplanar bandpass filters

Abstract

Single side metalliiation is one of the big advantages of co-

Accurate circuit models of CPW coupling elements for the design of compact quarter-wavelength band-pass filters

“…Due to their weak coupling degree, especially at low frequency, these elements can only be utilized to realize narrowpass bandwidth. To effectively increment the desired coupling degree, an alternative CPW parallel-coupled or overlapped structure was proposed in [12] and then employed to design a compact CPW filter [13]. Figure 3(b) shows the two CPW lines with short-ends aligned in parallel with the overlapped length T at the interval of a metallic gap.…”

“…Recent work has been shifted to explore the compact /4 CPW filters with good harmonic suppression [10,11]. But, due to the very limited coupling degree of these two elements, an alternative parallel-coupled CPW element was initiated in [12] and then employed in filter design [13]. In [13], its coupling behavior was intuitively characterized in terms of 2D even-and oddmode characteristic impedances, without including the dynamic effects caused by 3D CPW discontinuity.…”

Bandpass Filters on a Modified Multilayer Coplanar Line

“…The MCL was introduced as a good candidate for filter applications in [2], since it offers a wider range for a nearly constant characteristic impedance and provides more effective capacitive coupling between the resonators by locating them on the two sides of the substrate [2], [4]. Some MCL coupling structures for filters have been proposed in [3].…”

Characterization of semilumped CPW elements for Millimeter-wave filter design

“…To avoid dealing with the parasitic effects, use of structures with minimal parasitic features can be considered. Coplanar waveguide (CPW) line discontinuities are well characterized at microwave frequencies [1]- [3] and have been studied to some extent at higher frequencies up to 50 GHz [4]- [6]. However, modeling and characterization of such discontinuities at -band frequencies is rather limited.…”