This paper presents a 6-gon-shaped bandpass and notch filters for Cognitive Radio (CR) applications. The bandpass filter consists of a 6-gon-shaped multiple mode resonator with interdigital coupling at both ends. The notch filter is derived from bandpass filter by embedding four identical Embedded Open Stubs (EOS) nearby the multiple mode resonators that introduce narrow band suppression in the desired passband. Such bandpass filter with notching band is required in practical CR systems in order to effectively sense the spectrum and avoid the interference between the systems working in same environment with the same frequency. The filter is simulated using an electromagnetic solver, IE3D. The group delay obtained for bandpass filter is below 0.2[Formula: see text]ns. With the above structural features, the overall dimension of the filter is [Formula: see text][Formula: see text]mm2 and the fractional bandwidth (FBW) of the proposed bandpass filter is more than 100% with optimal performances in terms of insertion loss, return loss, group delay and phase.
Constant In-Band Group-Delay Acoustic-Wave-Lumped-Element-Resonator-Based Bandpass Filters and Diplexers
