Highly Selective Differential-Mode Wideband Bandpass Filter for UWB Application
Highly Selective Differential-Mode Wideband Bandpass Filter for UWB Application
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DOI：
10.1109/lmwc.2011.2104357
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发表时间：
2011-02
影响因子：
3
通讯作者：
T. B. Lim;Lei Zhu
中科院分区：
文献类型：
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作者：
T. B. Lim;Lei Zhu
提出了一种基于微带线的高选择性宽带差模带通滤波器，该滤波器具有良好的共模抑制性能。该滤波器在几何结构上类似于两级分支线结构，其改进型是将输入输出端口的两个垂直臂从λg /4拉伸到3 λg /4。其目的是实现更好的滤波器的选择性，通过增加两个额外的传输零点从扩展臂。在我们的设计中，一个具有两对外部端口的对称滤波器首先在差动和共模激励下分解成两个具有两个单端口的二等分滤波器。我们的研究表明，二端口二分电路在较低的UWB频带，即，3.1-5.1 GHz。然后设计并制作了宽带差模带通滤波器。基于电路模型、全波软件和实际测量的三组仿真结果都很好地吻合。在2.8-5.3 GHz的频率范围内实现了高选择性的差模通带，共模抑制约为20 dB。
A novel highly selective wideband differential-mode bandpass filter (BPF) with good common-mode suppression is proposed on microstrip line for ultra-wideband (UWB) application. The initial BPF is similar to a two-stage branch-line structure in geometry and its improved one is formed by stretching the two vertical arms on the input and output ports from λg /4 to 3 λg /4. The aim is to achieve better filter selectivity by adding two additional transmission zeros from the extended arms. In our design, a symmetrical filter with two pairs of external ports is firstly decomposed into two bisections with two single ports under differential- and common- mode excitations. Our study shows that the two-port bisection circuits achieve bandpass and bandstop filtering performances under the differential- and common-mode operation in the lower UWB band, i.e., 3.1-5.1 GHz. The wideband differential-mode BPF is then designed and fabricated. All the three sets of results from the simulations based on the circuit model, fullwave software, and actual measurement are found in good agreement with one another. A highly selective differential-mode passband is achieved in the frequency range of 2.8-5.3 GHz, with a common-mode suppression of about 20 dB.