New building blocks for modular design of elliptic and self-equalized filters
New building blocks for modular design of elliptic and self-equalized filters
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DOI：
10.1109/tmtt.2003.821923
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发表时间：
2004-02
影响因子：
4.3
通讯作者：
S. Amari;U. Rosenberg
中科院分区：
文献类型：
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作者：
S. Amari;U. Rosenberg
本文介绍了椭圆型、伪椭圆型和自均衡型滤波器的模块设计。第一个构建块是二阶的，并产生两个传输零（TZs），它们要么在实轴上，要么在虚轴上。将零点从实轴（线性相位响应）移动到虚轴（衰减极点）需要改变一个耦合系数的符号。第二个构建块是三阶结构，称为扩展重偶态，它允许在复平面的几乎任何地方生成两个TZs。该块的一个重要性质是它能够将两个TZs从复s平面的实轴移动到虚轴，而不改变其耦合系数的符号。第三个构件是三阶的，产生两个TZs，通过改变一个耦合系数的符号可以将其从实轴移动到虚轴。简单的波导结构来实现这些块引入验证，虽然这种一般方法是可行的所有谐振器滤波器类型。高阶滤波器是通过级联任意数量的这些构建块来模块化设计的。然后介绍了一种新颖的概念，该概念允许在高阶滤波器中对每对TZs进行独立控制。结果表明，即使假设耦合系数与频率无关，新概念允许N阶滤波器在不直接将源与负载耦合的情况下产生N个TZs。同样的方法可以用于设计和降低高阶椭圆和伪椭圆滤波器的灵敏度，使用其他构建块，如重态或不同阶数和性质的构建块的混合物。给出了测量结果和广泛的计算机仿真，以证明该概念的有效性和所设计滤波器的性能。
This paper introduces building blocks for modular design of elliptic, pseudoelliptic, and self-equalized filters. The first building block is of second order and generates two transmission zeros (TZs), which are either on the real or imaginary axis. Moving the zeros from the real axis (linear phase response) to the imaginary axis (attenuation poles) requires changing the sign of one coupling coefficient. The second building block is a structure of order three, called extended doublet, which allows the generation of two TZs practically anywhere in the complex plane. An important property of this block is its ability to move the two TZs from the real axis to the imaginary axis of the complex s-plane without changing the signs of its coupling coefficients. The third building block is of third order and generates two TZs, which can be moved from the real to the imaginary axis by changing the sign of one coupling coefficient. Simple waveguide structures to implement these blocks are introduced for validation, although this general approach is feasible for all resonator filter types. Higher order filters are designed modularly by cascading an arbitrary number of these building blocks. A novel concept, which allows the independent control of each pair of TZs in higher order filters, is then introduced. It is shown that the new concept allows a filter of order N to generate N TZs without directly coupling the source to the load even when the coupling coefficients are all assumed frequency independent. The same approach can be used to design and reduce the sensitivity of higher order elliptic and pseudoelliptic filters using other building blocks such as doublets or a mixture of building blocks of different orders and properties. Measured results and extensive computer simulation are presented to demonstrate the validity of the concept and the performance of the designed filters.