内置介质板开孔腔体电磁屏蔽效能拓扑模型

文中针对现有内置介质板腔体屏蔽效能拓扑模型中介质板等效导纳模型的局限性，考虑介质板高度、厚度与位置对介质板等效导纳模型的影响，建立内置介质板腔体屏蔽效能(BLT)方程拓扑模型。将传输线法、BLT方程拓扑模型与仿真结果进行对比，验证BLT方程拓扑模型的准确性和有效性。以300 mm×300 mm×120 mm开孔腔体为研究对象，分别探究其在3种不同谐振主模式下，介质板高度、厚度和位置对腔体屏蔽效能的影响。结果表明，改变介质板高度，腔体的谐振主模式不变，仅影响腔体屏蔽效能大小；腔体内部安装介质板可增强腔体屏蔽能力，但是介质板厚度过大，在一定范围内会削弱腔体屏蔽能力；距腔体孔阵0 mm～58 mm处安装介质板会削弱腔体屏蔽能力，距腔体孔阵100 mm～150 mm处安装介质板会增强腔体屏蔽能力。该结论可为机箱电磁屏蔽设计提供有效参考。

Topological Model of Electromagnetic Shielding Effectiveness of Cavity with Built-in Dielectric Plate

In this paper, aiming at the limitations of the equivalent admittance model of the dielectric plate in the existing shielding efficiency topology model of the built-in dielectric plate cavity, considering the influence of the height, thickness and position of the dielectric plate on the equivalent admittance model of the dielectric plate, the topological model of Baum-Liu-Tesche (BLT) equation of the shielding efficiency of the built-in dielectric plate cavity is established. The transmission line method and the topological model of BLT equation are compared with the simulation results to verify the accuracy and validity of the topological model of the BLT equation. Taking the open-hole cavity with a length of 300 mm, a width of 300 mm, and a height of 120 mm as the research object, the effects of dielectric plate height, thickness and position on cavity shielding efficiency under three different resonant modes are explored. The results show that changing the height of the dielectric plate keeps the resonance mode of the cavity unchanged, which only affects the shielding efficiency of the cavity. The installation of the dielectric plate inside the cavity can enhance the cavity shielding ability, but the thickness of the dielectric plate is too large, which will weaken the cavity shielding ability within a certain range. Installing the dielectric plate 0 mm~58 mm away from the cavity hole array will weaken the cavity shielding ability, and installing the dielectric plate 100 mm~150 mm away from the cavity hole array will enhance the cavity shielding ability. This conclusion can provide an effective reference for the design of electromagnetic shielding of shielded chassis.