%0 Journal Article
%T Compact Bandpass Filter with Wide Upper-Stopband Based on Spiral-Shaped Resonators and Spur-Lines
%A Liang Ma
%A Kaijun Song
%A Chunlin Zhuge
%A Yong Fan
%J PIER     Letters
%D 2012
%I EMW Publishing
%R 10.2528/PIERL11120203
%X A novel compact bandpass filter (BPF) with wide upper-stopband has been proposed in this paper. The structure is based on spiral-shaped resonators. Cross coupling is used to generate two transmission zeros at the lower and upper stopbands. Therefore, the out-of-band performance is improved. In addition, two spur-lines are adopted in the feed lines to reject the spurious response. The central frequency of this filter is at 2.45 GHz with a minimum insertion loss of less than 1 dB and a 3 dB bandwidth of 12.5%. Four transmission zeros are located at 2 GHz, 3 GHz, 5.5 GHz, and 8 GHz. The attenuation is greater than 20dB in a wide upper stopband up to 9.8 GHz.
%U http://www.jpier.org/pierl/pier.php?paper=11120203