New Stepped-Impedance Parallel-Coupled Line (PCL) Filters for Ultra-Wide Band (UWB) Applications

A new class of stepped-impedance parallel-coupled line filters is presented. The filters are compact, suitable for ultra-wide band frequency applications and exhibit broad upper stopband frequency characteristics. Several UWB filters were implemented at 1 and 3 GHz each demonstrating a measured fractional bandwidth of over 111% and each exhibiting a first spurious passband located at five times the fundamental passband center frequency. Furthermore a 6.85 GHz filter was fabricated and showed excellent electrical performance.