In this letter, new patterns of symmetric trisection bandpass filter (BPF) with reflection-type half-wave resonators, mixed cross-coupling, and different paths for signal propagation are discussed. The various coordinates of the conductive connection of loads to the end half-wave resonators are used in the filter. This leads to different signal paths from input to output of the filter. Due to the various connections of loads and mixed cross-coupling, satisfying condition $K_{13} = 0$ , the same filter has different frequency responses. When we use one port position, two transmission zeros, located on the $\sigma \! $ -axis of the complex plane $s = \sigma + j\Omega $ , are generated, and we obtain a flat group delay. If another port position is used, two transmission zeros are generated on the $j\Omega $ -axis, $\Omega = (\omega /\omega _{0} - \omega _{0}/\omega)$ /fractional bandwidth (FBW), and a quasi-elliptic response is presented. In both cases, two transmission zeroes are equidistant relative to $s =0$ and they are controlled by a mixed coupling coefficient. The results of the measurements and simulation are presented.

中文翻译：

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具有混合交叉耦合和不同信号传播路径的三等分带通滤波器

在这封信中，讨论了具有反射型半波谐振器、混合交叉耦合和不同信号传播路径的对称三等分带通滤波器 (BPF) 的新模式。滤波器中使用了负载到端部半波谐振器的导电连接的各种坐标。这导致从滤波器的输入到输出的不同信号路径。由于负载的各种连接和混合交叉耦合，满足条件 $K_{13} = 0$ ，同一个滤波器有不同的频率响应。当我们使用一个端口位置时，两个传输零点位于 $\西格玛\! $- 复平面的轴 $s = \sigma + j\Omega $ , 产生，我们得到一个平坦的群延迟。如果使用另一个端口位置，则会在端口上生成两个传输零点 $j\欧米茄 $ -轴， $\Omega = (\omega /\omega _{0} - \omega _{0}/\omega)$ /分数带宽（FBW），并呈现准椭圆响应。在这两种情况下，两个传输零点相对于 $s = 0$ 它们由混合耦合系数控制。给出了测量和模拟的结果。