Coupling Matrix-Based Design of Waveguide Filter Amplifiers
Coupling Matrix-Based Design of Waveguide Filter Amplifiers
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DOI：
10.1109/tmtt.2018.2871122
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发表时间：
2018-10
影响因子：
4.3
通讯作者：
Yang Gao;J. Powell;X. Shang;M. Lancaster
中科院分区：
文献类型：
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作者：
Yang Gao;J. Powell;X. Shang;M. Lancaster
本文将传统的无源滤波器耦合矩阵理论推广到同时具有滤波和放大功能的“滤波-放大器”的设计中。对于这种方法，额外的元素被添加到标准耦合矩阵来表示晶体管。根据对滤波器和晶体管小信号参数的要求，可以综合出“滤波器-放大器”的有源耦合矩阵。采用有源耦合矩阵，对滤波器的最后一个谐振器(与晶体管相邻)以及它们之间的耦合进行了数学上的修正，以提供具有放大功能的切比雪夫响应。虽然晶体管具有复阻抗，但通过选择耦合结构和谐振器频率，它可以匹配到滤波器输入。这是特别有用的，因为滤波器谐振器可以是与放大器(例如，微带)不同的结构(例如，波导)。这里以X波段滤波放大器为例进行了实现，但技术是通用的。
This paper extends the conventional coupling matrix theory for passive filters to the design of “filter-amplifiers,” which have both filtering and amplification functionality. For this approach, extra elements are added to the standard coupling matrix to represent the transistor. Based on the specification of the filter and small-signal parameters of the transistor, the active $N + 3$ coupling matrix for the “filter-amplifier” can be synthesized. Adopting the active coupling matrix, the last resonator of the filter (adjacent to the transistor) and the coupling between them are modified mathematically to provide a Chebyshev response with amplification. Although the transistor has a complex impedance, it can be matched to the filter input by the choice of the coupling structure and the resonator frequency. This is particularly useful as the filter resonators can be of a different construction (e.g., waveguide) to the amplifier (e.g., microstrip). Here, an X-band filter-amplifier is implemented as an example, but the technique is general.