Synthesis Model and Design of a Common-Mode Bandstop Filter (CM-BSF) With an All-Pass Characteristic for High-Speed Differential Signals
Synthesis Model and Design of a Common-Mode Bandstop Filter (CM-BSF) With an All-Pass Characteristic for High-Speed Differential Signals
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DOI：
10.1109/tmtt.2014.2328314
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发表时间：
2014-06
影响因子：
4.3
通讯作者：
Tsui-Wei Weng;Chung-Hao Tsai;Chung-hao Chen;Dong-ho Han;Tzong-Lin Wu
中科院分区：
文献类型：
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作者：
Tsui-Wei Weng;Chung-Hao Tsai;Chung-hao Chen;Dong-ho Han;Tzong-Lin Wu
通过在两层印刷电路板 (PCB) 上使用带有蜿蜒信号线的 C 形图形接地结构 (PGS)，提出了一种针对差分信号具有全通性能（从直流到 9 GHz）的新型共模带阻滤波器 (CM-BSF)。该技术可以在相关频率内成功地生成两个接近的共模传输零点。建立了相应的等效电路模型来预测滤波器的行为，并根据电路模型推导了共模传输零点的公式。接下来，开发了一种设计方法并提出了合成程序。根据该过程，在两层 PCB 上合成并制造了宽带 CM-BSF。此外，仿真和实验结果验证了该技术并显示了所提出的 CM-BSF 的优异性能。结果表明，在 1.9 至 8.9 GHz 范围内，共模噪声可被抑制超过 10 dB，分数带宽 (FBW) 为 130%，而差模插入损耗在直流至 9 GHz 范围内可保持在 3 dB 以下。电气尺寸仅为0.21 λg ×0.21 λg，其中λg为阻带中心频率的波长。综上所述，所提出的CM-BSF具有成本低（两层）、几何结构简单、尺寸紧凑和共模FBW大的优点。最重要的是，由于滤波器的全通特性，可以保持数字差分信号良好的信号完整性。
A new common-mode bandstop filter (CM-BSF) with an all-pass performance (from dc to 9 GHz) for differential signals is proposed by using a C-shaped patterned ground structure (PGS) with meandered signal lines on a two-layer printed circuit board (PCB). This technique can successfully generate two close transmission zeros in common-mode within the frequencies of concern. A corresponding equivalent circuit model is established to predict the filter behaviors, and a formula for common-mode transmission zeros is derived based on the circuit model. Next, a design method is developed and a synthesis procedure is proposed. According to the procedure, a wideband CM-BSF is synthesized and fabricated on a two-layer PCB. In addition, the simulation and experiment results are demonstrated to verify the technique and show excellent performance of the proposed CM-BSF. It is shown that common-mode noise can be suppressed over 10 dB from 1.9 to 8.9 GHz with 130% fractional bandwidth (FBW) while the insertion loss of differential-mode can be kept less than 3 dB from dc to 9 GHz. The electrical size is only 0.21 λg ×0.21 λg, where λg is the wavelength of the stopband central frequency. To sum up, the proposed CM-BSF has merits of low cost (two layer), a simple geometric structure, a compact size, and a large common-mode FBW. Most importantly, the filter can keep good signal integrity of the digital differential signals due to its all-pass characteristic.