High-Performance and Compact UWB SIW Bandpass Filter with a Notch Band

A high-performance and compact ultra-wideband (UWB) substrate integrated waveguide (SIW) bandpass filter (BPF) with a notch band is proposed. The SIW technology provides an effective solution for designing a high-performance filter. A novel loaded structure defined as double complementary interdigital cell (DCIC) is developed and loaded on the SIW to generate a low-pass characteristic with an independent and controllable notch band. Combined with the inherent high-pass characteristics of the SIW, good UWB passband with an alterable notch band is obtained. Two rectangular slots are introduced to improve the impedance matching of the input and output ports. A pair of open stubs are subtly inserted into the rectangular slots to produce an additional transmission zero (TZ) close to the upper passband for sharpening rejection skirt and improving the out of band performance. At last, a prototype of UWB filter is investigated, designed, manufactured, and experimented. Excellent simulated and measured results are obtained.