Compact Tri-Notched Ultrawideband Bandpass Filter Design Using CSRR, DGS, and FMRR Configurations

The folded multiple-mode resonators with complementary split ring resonator (CSRR), and defected ground structures (DGS) are introduced for notched ultrawideband (UWB) bandpass filter (BPF) design in this article. Using the CSRR, FMRR, notched wide-band BPF, a notch response can exist in the UWB passband for blocking the interference. Adjusting the size factor of CSRR, the wide tuning ranges of notch frequencies included the desired frequencies of 5.2/5.8 GHz are achieved. The lower insertion loss (0.31 dB), higher rejection level (-48.40 dB), wider bandwidth (FBW 75%), and wider stopband (extended to 2.01 f(0) below -20 dB rejection level) of UWB band at the central frequency f(0) = 4.58 GHz are obtained. Second, design a CSRR, DGS, FMRR, tri-notched UWB filter, the wider bandwidth (3.1-9.8 GHz) with FBW = 126%, lower insertion loss (0.26 dB), and higher rejection level (-44 dB) of UWB band at central frequency f(0) = 5.6 GHz are presented. Using the CSRR and interdigital couple, three notch responses can exist in the UWB passband for blocking the interference signals. Adjusting the size factor of CSRR and interdigital couple, the wide tuning ranges of notch frequencies included the desired frequencies of 5.18/6.10/8.08 GHz are achieved. The wide tuning ranges of three notched frequencies cover from 5.0 to 8.4 GHz. It is a simple way to control the notch responses. (c) 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:571-579, 2014.