Design of a novel slotted bandpass-bandstop filters using U-resonator and suspended multilayer-technique for L/X-band and Wlan/WiMax applications

A novel compact microstrip bandpass-bandstop filters realized using a new U-DGS resonator and cascaded method is proposed. Basing on the topology of the designed bandpass filter and on multilayer method, a novel compact bandstop is optimised developed. The proposed BPF and BSF are very compact due to the slow-wave effect and have low loss in the passband and stopband respectively. The both filters have sharp transition regions due to the presence of transmission- and reflexion-zeros on both sides of its passband and stopband. The BPF has a center frequency, bandwidth and insertion loss are 3.4 GHz, 40%, and 0.5 dB respectively. The BSF is designed with a center frequency of 5 GHz and covers a stopband of 4 GHz. The simulated and measured results show good agreement and validate the proposed approach.