主要研究微带交叉耦合滤波器的简化设计。通过约束传输零点之间的关系, 简化了带通滤波器交差耦合的拓扑结构, 同时又较好保持了带通滤波器带外的抑制能力。在利用微带结构实现时, 采用了谐振器顺序耦合的结构, 降低了滤波器微调的难度。同时在第一和第四谐振器间增加一段传输线以引入交叉耦合, 通过调整引入传输线的位置等可调整相应传输零点的位置, 增加了滤波器设计的灵活性。仿真结果验证了相关方法的有效性。

Simplified design of microstrip cross coupled filter is studied. Cross coupling topology of bandpass filter is simplified through suitable constraints on its transmission zeros, while keeping the good stopband performance at the same time. Microstrip structure is considered here to realize cross coupled bandpass filter. Series coupling structure is adopted to minimize the difficulty of tuning the filter. Cross coupling is realized by adding transmission line between the first and the forth resonators. Transmission zeros could be altered by changing the positions of the transmission line, thus additional design flexibility could be obtained. Simulated results validate the proposed methods.