【摘要】 为了提高对有孔屏蔽腔内电路的有效保护性能。介绍了用传输线法分析有孔矩形腔屏蔽效能的基本原理。将基本公式作进一步修正,使其能计算矩形腔内装有印刷电路板的情形。并对修正的传输线模型计算公式进行了扩展,使之能计算任意极化方向时的情况。计算结果表明:当频率低于主谐振频率时,测量点离孔缝越近,耦合进腔体的电磁能量越多;屏蔽效能随极化角度的递增而增加;低频段的屏蔽效能比高频段的要好;装有电路板腔体的屏蔽效能比空腔的要好,这在谐振区域内尤为突出;电路板尺寸越大屏蔽效能越好。根据计算结果,提出了设计屏蔽腔及其腔内电子设备的建议。更多还原

【Abstract】 In order to improve the protection effectiveness of enclosure loaded PCB with aperture, the basic theory of transmission line method is first introduced to analyze shielding effectiveness of rectangular cavity. The basic formulas are then revised to calculate the case when the PCB is set in rectangular cavity. The revised formulas are expanded to arbitrary angle of polarization. Computation results indicate that the coupling energy increases as the observational point closes to the enclosure, the shielding effectiveness is better as the polarization angle increase, and the shielding of low frequency is better than that of high frequency. In the same conditions, the shielding effectiveness of enclosure with aperture containing a PCB is better than that of loaded one especially in the resonance frequency bandwidth, the shielding effectivenessis much better as the size of PCB increases. Some suggestions from calculation results are presented for design of shielding and electronic equipment in the body of shielding.更多还原