Planar microstrip UWB bandpass filter with quad notched bands and high selectivity

Background: Aiming at solving the problems of large design size and insufficient number of notched band for traditional ultra-wideband (UWB) filters, a planar compact microstrip UWB bandpass filter (BPF) with quad notched bands and good selectivity is proposed using a modified multiple-mode resonator (MMR) and defected ground structure (DGS). Methods: The MMR consists of a stepped impedance stub above and two pairs of open-circuited stubs on both sides, which c an generate the passband and double notched bands of UWB filter, the other two notched bands are obtained by DGS. Results: The UWB filter with quad notched bands respectively centered at 3.9GHz, 5.7GHz, 7.9GHz, and 9.8GHz is fabricated and measured. Conclusion: The measured results are basically consistent with the simulated results, which proves the correctness and practicability of the UWB filter.

A Novel Compact UWB Bandpass Filter with Quad-Notched Bands Based on S-SCRLHs Resonator

A novel compact ultra-wideband (UWB) bandpass filter (BPF) with a quad band-notched function using S-SCRLHs (splitted simplified composite right/left-handed) resonator is presented. The S-SCRLHs resonator, which exhibits quadruple resonance, is realized by coupling double S-SCRLH resonator. The S-SCRLHs resonator is integrated into a conventional UWB BPF. The notched frequencies can be adjusted according to specification by altering the S-SCRLHs resonator. Band-rejected filtering properties around the C-band satellite communication band, 5.2 GHz WLAN band and the X-band satellite communication band are generated. The notching frequencies are located at 4.2/5.2/6.3/7.8 GHz. Both simulated and measured results are provided with good agreement. Compared with other BPFs, the proposed BPF has the advantages of compact size, multi-stopband and good selectivity.