Simple Ultra-wide Band Band-Pass Filters with Dual- and Quad-Notched Bands

A simple ultra-wideband (UWB) band pass filter (BPF) with dual-or quad-notched bands based on embedded open stubs and shunt short-circuited stubs structure is investigated. Single and double embedded open stubs are analyzed and employed to create the desired rejection bands. A broadside-coupled micro strip-coplanar waveguide (CPW) structure is adopted to build a simple UWB BPF prototype. Two identical shunt short-circuited stubs between the embedded stubs and UWB BPF are employed to improve the matching performance. The stub structure with little interference of each notched band, can be applied in UWB system to avoid several existing radio systems. Simulation and the design of the UWB BPFs with rejection bands according to FCC's spectrum mask are presented. The dual- and quad-notched UWB BPFs are fabricated and measured to validate the feasibility of this design. Good agreements between the predicted and measured results are achieved.