PCB板折叠形成线模块设计与实验

Design and experimental investigation of folded parallel-plate pulse forming line based on PCB

采用FR-4型PCB板材为传输介质,设计了一种五条线并联的形成线模块。为优化形成线电场分布,绝缘介质层内部嵌有屏蔽电极,分析得到内嵌导体对形成线的特征参量以及传输特性无影响;形成线绝缘介质层厚度为4mm,耐受电压超过200kV,根据绝缘寿命公式分析,形成线可以在50～80kV长时间工作;将PCB板折叠线通过并联以及封装组成形成线模块,外观尺寸为700mm×550mm×40mm,特征阻抗为5.35Ω,通过搭建Blumlein装置进行实验,在充电50kV条件下,测得输出电压为45kV,脉冲半高宽140ns,平顶宽度75ns,前沿65ns。

Using the FR-4 as the dielectric materials, a pulse forming line （PFL） module was developed by attaching five PCB PFLs in parallel. In order to optimize electric field distribution, a shielded electrode was inserted in the dielectric materials, and the theoretical analysis shows the shielded electron has no effect on the parameter and transmission characteristics of the PFL. The PFL can withstand more than 200 kV with a insulating layer thickness of 4 mm. According to the lifetime calculation equa- tion, it is found that the PFL has a long lifetime when the charging voltage is 50-80 kV. The size of PFL module is 700 mm× 550 mm×40 mm, and the characteristic impedance of it is 5.35 Ω. When the PFL module is used in a Blumlein manner and charged to 50 kV, the output voltage on the match-load of 45 kV, full width at half magnitude （FWHM） of 140 ns, flat top of 75 ns and time rise of about 65 ns are obtained.