Two bandpass filters with the cross shaped resonator and parallel coupled lines are proposed. It has two fixed transmission zeros (TZ) which are located at 0 and 2pi. With the assistance of two types of parallel coupled line, two bandpass filters have other two TZs. Two TZs only depend on the odd and even mode impedance of open parallel coupled line stubs or short parallel coupled line stubs. By adjusting the odd- and even-mode impedance values, two TZs can be adjusted and the frequency selectivity of the bandpass filters are improved. Two bandpass filters are fabricated and measured. The experimental results are basically consistent with the simulation results, which verifies the filter design method.

提出了两个带有十字形谐振器和平行耦合线的带通滤波器。它有两个固定的传输零点 (TZ)，位于 0 和 2pi。在两种平行耦合线的辅助下，两个带通滤波器具有另外两个TZ。两个 TZ 仅取决于开路并联耦合线短截线或短并联耦合线短截线的奇偶模阻抗。通过调整奇偶模阻抗值，可以调整两个TZ，提高带通滤波器的频率选择性。制作并测量了两个带通滤波器。实验结果与仿真结果基本一致，验证了滤波器设计方法。