| 摘要: |
| 设计了一种梳状微带平行耦合线窄带带通滤波器，仅应用两腔结构就实现了带外5个
传输零点。通过微带线开路枝节，平行耦合线结构，以及馈电位置和两个梳状线谐振器之间
的耦合，在通带附近引入了3个传输零点；四分之一波长平行耦合线接地短路结构，在带外
高频产生额外两个传输零点，进而可有效抑制零点频率附近的杂波干扰。实测结果表明，设
计的滤波器中心频率为238 GHz，相对带宽45%，对低频抑制大于22 dB，带外
5个零点位置与计算仿真结果吻合很好。该新型滤波器结构简单紧凑，带外抑制高。 |
| 关键词: 微带带通滤波器 传输零点 微带耦合线 开短路枝节 |
| DOI： |
|
| 基金项目: |
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| Design of a microstrip bandpass filter with multiple transmission zeros |
| CAI De-shui,LEI Zhen-ya,XIE Yong-jun,NING Gao-li |
| () |
| Abstract: |
| A microstrip hairpin parallelcoupled narrowband bandpass filter(BPF) is p
roposed, which uses only two coupled resonators to realize five transmission z
eros. Due to the opencircuited stubs, the opencircuited parallel coupledli
nes
, tapped feeding position and coupling between two hairpin resonators, three tra
nsmission zeros in the vicinity of the passband are introduced. Two quarterwav
e
length parallel coupledlines sharing the same via hole grounding can contribut
e
two additional transmission zeros beyond the passband, which can suppress the f
requency interference near the zero points. Measured results show that the filte
r has the fractional bandwidth of 4.5% with the center frequency of 2.38 GHz and
a minimum outband loss of 22 dB in the lower band. The measured positions of
t
he five transmission zeros agree well with the analytical model and numerical si
mulations. The proposed bandpass filter has such advantages as compact size, sim
ple structure and high selectivity in the stopband. |
| Key words: microstrip bandpass filter(BPF) transmission zeros microstrip coupled lines open or short stubs |
《电讯技术》编辑部 