交叉耦合微带带通滤波器

Cross-coupled bandpass filter with microstrip lines

针对无线通信系统小型化的要求,设计了一种带有交叉耦合的带通滤波器,该滤波器采用带过孔的终端短路式耦合线为谐振单元,同时加入了交叉耦合线改善滤波特性;整个结构紧凑,具有插入损耗低、选择性高、带外抑制度佳等特点,实测结果与仿真吻合较好,中心频率为4.2 GHz,3 d B带宽为400 MHz,驻波比小于1.5,体积仅为8 mm×6 mm×0.7 mm。

A cross-coupled bandpass filter with microstrip lines was proposed for the miniaturization of wireless communication system. This filter used coupled microstrip line with short circuited via as resonance unit and added cross-coupled line to improve the performance. The test results show that the filter has the advantages of small size, high selectivity, sideband steep and high stopband rejection. The measured results of the filter agree well with the simulation. The filter has a central frequency of 4.2 GHz, a 3 d B bandwidth of 400 MHz, VSWR of less than or equal to 1.5. The size of the filters is only 8 mm×6 mm×0.7 mm.