带状线低通滤波器的等效电路模型研究

所涉及的滤波器结构中包含开路端、T型接头等不连续性部分,因此在分析时应充分考虑到这些不连续部分所产生的传输损耗。基于传输线基本理论和矩量法(MoM),通过曲线拟合获得了偏心带状线开路端电容的解析公式,然后依据已有的微带线不连续性等效电路理论,提出了偏心带状线低通滤波器的等效电路模型。经实例验证发现,所得模型的计算结果与IE3D软件仿真结果吻合良好,而传输线理论法未考虑上述传输损耗,计算结果存在明显偏差。

Research on Equivalent Circuit Model of the Stripline Low-pass Filter

The filter presented in this paper contains different kinds of discontinuities, such as open circuits, T-junctions and so forth, therefore we should give full consideration to transmission losses of these discontinuities. Based on basic transmission line theory and the moment method (MoM), the analytic expressions of open circuit capacitance for asymmetric stripline by curve-fitting, and then we successfully obtain the equivalent circuit model of the asymmetric stripline low-pass filter on the basis of microstrip lines discontinuity equivalent circuit theory method. Through the practical example, we find the results of our obtained model are in good agreement with IE3D results, while transmission line theory method leads to obvious deviation without considering transmission losses.