Parallel-coupled Bandpass Filter Using Interdigital Fingers and Defected Ground Structure
The traditional microstrip line coupling bandpass filter has the shortcoming of the 2f0, 3f0, 4f0, and 5f0 spurious, and this is harmful to the RF communications system bandwidth and seffectivity. In recent years, there have been a number of studies to improve bandwidth e±ciency and have high seffectivity 1-5. This paper we used the microstrip line manufacture lump compensation effectric capacity 0.046 pf of the high frequency capacitor, achieved the suppression of the spurious 2f0 and 4f0 more than 40 dB. The g1, g2, g3, and g4 as Fig. 1 show that this sub-capacitor has not a?ected of the even mode signal, but can a?ect the odd mode signal. So, can cause the coupler at center frequency of the even mode signal and the odd mode signal path arrive the end point together. Therefore may restrain the 2f0 and 4f0 spurious. Then we used four DGS (Deffected Ground Structure) resonators to form 6 GHz low pass filter, serially connects in the input and output port place separately, as Fig. 1 DGS shows, its can restrain 3f0, 4f0 and the 5f0 spurious about 7 to 12 GHz. We proposed the effectric capacity compensation using the microstrip line manufacture extremely small capacitance value 0.046 pf which can improve the second spurious of the phase velocity does not match of the parallel coupling bandpass filter. In addition also resists the characteristic using the DGS parallel connection resonant. By four step DGS series, adjusts each gap width to cause each pole spot to fall in the different frequency band, but the square fixed roll off invariable increases the cut-o? region frequency band depth. Therefore may compose small area characteristic steep broad closure frequency band 6 GHz low pass filter. Finally, the parallel coupling bandpass filter recombination the interdigital fingers of minimum capacity and DGS, forms a new also the broad closure bandwidth of the parallel coupling bandpass filter. From the simulated results, we found that it can achieve the suppression of the 2f0, 3f0, 4f0, and 5f0 spurious more than 40 dB, and the stopband even reaches to 12 GHz, as Fig. 2 shown.
Man-Long Her Wen Ko Ming-Wei Hsu
The Graduate Institute of Electrical and Communications Engineering Feng Chia University, Taiwan, Ch The Graduate Institute of Electrical and Communications Engineering Feng Chia University, Taiwan, Ch
国际会议
Progress in Electromagnetics Research Symposium 2007(2007年电磁学研究新进展学术研讨会)(PIERS 2007)
北京
英文
1071-1072
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）