Scattering by linearly vibrating objects
Scattering by linearly vibrating objects
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线性振动物体的散射
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
R. Mack
中科院分区：
文献类型：
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作者：
R. Kleinman;R. Mack
从理论上和实验上研究了平面波入射到完美传导的线性振荡物体上的散射问题。理论分析精确到 v/c 阶，其中 v 和 c 分别表示物体和光的速度，表明目标振荡仅在相位上改变静止目标的散射远场。假设振荡是周期性的，并且该周期被证明会影响到散射场。调制的频谱分析表明，功率分布随着运动的形状、入射场的波长以及入射方向和接收器方向上的振荡投影的大小而变化。已经计算了方形、三角形和正弦目标运动的功率谱，并且通常发现高次谐波中的功率含量随着卡地亚频率和振荡幅度的增加而增加。对于沿入射方向正弦移动的物体产生的反向散射，当 d > 0.23lambda 时，一次谐波的功率会超过载波频率的功率，其中 d 是振荡幅度。这些计算结果与 X 波段振动盘散射场相位调制的实验测量结果一致。实验结果是通过 10 GHz 的连续波反向散射设备获得的，该设备利用单独的隧道天线进行发射和接收。该设备的接收部分经过修改，可以分别显示后向散射信号在时间和频率上的相位调制和幅度调制特性，以及整体调制包络的特性。由小至 pm 0.001 in 的目标振荡引入的相位调制很容易检测到，百分之几的幅度调制也是如此。
The scattering problem for a plane wave incident upon a perfectly conducting linearly oscillating object is investigated both theoretically and experimentally. The theoretical analysis, accurate to order v/c where v and c axe the velocities of object and light, respectively, shows that the target oscillation changes the scattered far field of a motionless target only in phase. The oscillation is assumed to be periodic, and this period is shown to be impressed on the scattered field. Spectral analysis of the modulation shows that the power distribution varies with the shape of the motion, wavelength of the incident field, and the magnitude of the projections of the oscillation in the direction of incidence and receiver. Power spectra have been calculated for square, triangular, and sinusoidal target motion and, in general, the power content in the higher harmonics is found to increase with cartier frequency and magnitude of oscillation. For backscattering from an object moving sinusoidally along the direction of incidence, the power in the first harmonic is shown to exceed that at the carrier frequency when d > 0.23lambda where d is the magnitude of the oscillation. These calculations are shown to agree with experimental measurements of the phase modulation of the field scattered from a vibrating disk at the X -band. Experimental results were obtained with continuous wave backscatter equipment at 10 GHz that utilized separate tunnel antennas for transmitting and receiving. The receiving section of this equipment was modified to separately display phase modulation and amplitude modulation characteristics of the backscattered signal in both time and frequency, as well as characteristics of the overall modulation envelope. Phase modulations introduced by target oscillations as small as pm 0.001 in were readily detected, as were amplitude modulations of a few percent.