微波脉冲与不同形状带矩形孔缝腔体耦合的数值模拟

 利用时域有限差分法对微波脉冲与带矩形孔缝的矩形和圆柱形腔体两种系统的线性耦合过程进行了研究。首先用数值方法分析了耦合过程中的场增强现象、脉宽展开现象和腔体调制现象，并发现了耦合过程中微波脉冲存在频谱分离现象。当微波脉冲的电场与孔缝窄边平行时，借助耦合函数对两个系统内部耦合场的分布特性进行了研究，结果表明在与孔缝窄边垂直的平面内，越靠近腔体壁，耦合场越弱。此外，两种腔体内部的耦合场在腔体截面内均呈现准周期振荡分布，矩形腔体内部耦合场振荡的幅值较均匀，而圆柱形腔体内部耦合场幅值在其截面中心附近区域最大；除了孔缝附近区域外，圆柱腔体轴线两端的耦合场远大于矩形腔体相应的耦合场。最后，研究了孔缝耦合共振频率与孔缝尺寸的关系，结果表明系统耦合共振频率不只与孔缝尺寸有关，而是由孔缝尺寸和腔体形状及其对微波脉冲的反射特性共同决定。

Numerical study on coupling of microwave pulses into different shaped cavities through slots

Linear coupling processes of microwave pulses into rectangular and cylindrical cavities with narrow rectangular slots are investigated by finite-difference time-domain (FDTD) method. Phenomena of field enhancement, cavity modulation, and pulse width stretch are observed, especially the spectrum separation effect. When the electrical field of microwave pulses is parallel to slot short-side, the distribution of coupling microwave electrical fields inside the two cavities are calculated. The coupling electrical field in the plane, which is perpendicular to slot short-side, decreases rapidly near the inner wall of the cavity. In addition, in the cross-sections of the cavities, coupling electrical fields oscillate in a quasi-periodic manner, and the field amplitude is relatively uniform for the