平面波照射下屏蔽腔内滤波器的分析

电磁波会通过屏蔽腔上的孔缝耦合到腔内并在电路板上激励起干扰电压,影响电子器件的正常工作。该文采用时域数值仿真,计算了一个微带线耦合滤波器分别在自由空间和屏蔽腔内时,在平面波的照射下端口电压响应,并通过Fourier变换得到频域响应。计算了不同入射电场方向、滤波器在屏蔽腔内的不同摆放位置对端口电压的影响,得到了各种情况下端口电压随频率的变化曲线。结果表明,放置在屏蔽腔中时,受屏蔽腔谐振特性的影响,滤波器的散射参数会变差,端口电压的频率响应也由自由空间的连续分布变为分立的谐振峰。在放置电路板时应尽量避免使滤波器的走线方向和开缝的方向垂直,同时还要考虑不同位置对端口电压的影响。

Analysis on microstrip filter in the shielding enclosure illuminated by a plane wave

Electromagnetic waves couple into shielding enclosures through slots and apertures to induce voltages on the circuit board that interfere with the electric components.This paper presents an analysis of the port voltage of a microstrip filter in the free space and in the enclosure illuminated by a plane wave.Time domain simulation is used,and the frequency response is calculated using Fourier transform.The influences of various electric field directions and positions in the enclosure are also analyzed to calculate the voltage variations with frequency.The results show that the resonance characteristics of the enclosure adversely affect the scattering parameter,with the port voltage frequency response varing from continuous to a group of individual resonant peaks.Circuit boards should be placed so that the filter microstrip is not perpendicular to the slot.The influence of the various positions in the enclosure should also be considered.