一种基于信号干扰技术的谐波滤波器设计

A harmonic filter design based on the principle of signal interference

采用信号干扰技术原理设计了一种微带线结构的微波滤波器,将目标频率的二次、三次谐波进行了一定程度的抑制。滤波器以厚度为0.381 mm的高工艺精度陶瓷材料作为基板,依托薄膜工艺进行金属层的制作。为达到宽阻带的抑制效果以及使过渡带更为陡峭,滤波器的电路结构上采用了两个信号干扰单元级联,并添加耦合环增加陷波点的方式。滤波器对1.2~1.3 GHz频段信号的二倍频、三倍频进行了有效的抑制,实现了二次谐波抑制度大于30 dB、三次谐波抑制度大于20 dB的抑制效果。滤波器通带内的插入损耗小于0.38 dB,带内回波损耗大于16 dB。滤波器外形尺寸为20.4 mm×10 mm×0.381 mm。该滤波器整体结构较为简单,易于工艺制作,能够有效地降低生产成本,利于批量制造。

A microwave filter with a microstrip structure was designed by using the signal interference principle to suppress the secondary and third harmonics of the target frequency.The high process precision ceramics with the thickness of 0.381 mm was used as the substrate,and the metal layer was made by thin film process.In order to achieve the inhibitory effect of widening the stop band as well as to make the transition band of the filter steeper,the filter circuit structure two cascaded signal interference units was adopted in the filter circuit structure,and a coupled ring was added to increase the transmission zero point.As a result,the double frequency and triple frequency of the 1.2-1.3 GHz band signal was suppressed effectively,and the inhibitory effect was realized.The secondary harmonic suppression system is greater than 30 dB and third harmonic suppression system is greater than 20 dB.The insertion loss in the passband of the filter is less than 0.38 dB,and the return loss is greater than 16 dB.The size of the filter is 20.4 mm×10 mm×0.381 mm.The overall structure of the filter is relatively simple and easy to fabricate,which can effectively reduce the production cost and facilitate mass manufacturing.