基于耦合传输线的宽上通带窄带带阻滤波器设计

微波系统中常常采用窄带带阻滤波器抑制高功率发射机的非线性谐波输出和带通滤波器的寄生通带, 其设计难点主要是如何消除其中心频率f0的三倍(3f0)频处的寄生阻带问题. 该文通过在平行耦合传输线滤波节开路端采用加载电容的方式, 有效解决了基于平行耦合传输线的窄带带阻滤波器在上通带3f0处具有寄生阻带的问题, 展宽了该类带阻滤波器的上通带带宽, 拓宽了其适用范围. 采用该方法, 研制了一个中心频率在5.3GHz的窄带带阻滤波器, 实测结果表明, 该带阻滤波器具有良好的上通带带宽.

Design of a Narrow Band-Stop Filter with Wide Upper Passband Based on Parallel-Coupled Line

The narrow-band band-stop filters are often used in microwave systems to suppress the nonlinear harmonic output of high-power transmitters and the parasitic passband of band-pass filters. The difficulty of the design is to eliminate the parasitic stopband at three times the center frequency f0. This paper effectively solved the problem of parasitic stopband at 3f0 and largely extended the upper passband by means of loading a lumped capacity at the open end of the parallel-coupled line. According to this method, a narrow band-stop filter with a center frequency at 5. 3 GHz has been presented. The test result shows that this filter has a good performance at upper passband.