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 雷达学报  2018, Vol. 7 Issue (1): 75-82  DOI: 10.12000/JR17093 0

### 引用本文

Chen Gang, Dang Hongxing, Tan Xiaomin, et al. Scattering properties of electromagnetic waves from randomly oriented rough metal plate in the lower terahertz region[J]. Journal of Radars, 2018, 7(1): 75-82. DOI: 10.12000/JR17093.

### 文章历史

(中国空间技术研究院西安分院   西安   710000)
(东南大学毫米波国家重点实验室   南京   210096)

Scattering Properties of Electromagnetic Waves from Randomly Oriented Rough Metal Plate in the Lower Terahertz Region
Chen Gang, Dang Hongxing, Tan Xiaomin, Chen Hui, Cui Tiejun
(China Academy of Space Technology (Xi’an), Xi’an 710000, China)
(State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China)
Foundation Item: The National Ministries Foundation
Abstract: An efficient hybrid algorithm is proposed to analyze the electromagnetic scattering properties of an infinitely thin metal plate in the lower terahertz (THz) frequency region. In this region, the metal plate can be viewed as a perfect electrically conductive object with a marginally rough surface. Hence, the THz scattered field from the metal plate can be divided into coherent and incoherent parts. The physical optics and truncated-wedge incremental-length diffraction coefficients methods are used to compute the coherent part, whereas the small perturbation method is used to compute the incoherent part. Then, the radar cross section of the rough metal plate surface is computed by the multilevel fast multipole and proposed hybrid algorithms. The numerical results show that the proposed algorithm has a good accuracy when rapidly simulating the scattering properties in the lower THz region.
Key words: Terahertz scattering    Physical optics    Truncated-wedge incremental-length diffraction coefficients    Small perturbation method    Radar cross section
1 引言

2 微粗糙目标散射理论

2.1 物理光学法

 图 1 PO散射示意图 Fig.1 Schematic diagram of the scattered field with PO method

2.2 随机导体粗糙面相干散射RCS

 图 2 粗糙表面散射示意图 Fig.2 Schematic diagram of rough surface scattering

V=kiks, VzV沿着z方向的分量。h是表面高度起伏均方根。

2.3 随机导体粗糙面非相干散射RCS

2.4 微扰法

I 的表达式为：

2.5 高斯粗糙表面的目标建模

 图 3 无限薄粗糙平板示意图 Fig.3 Schematic diagram of an infinitely thin rough PEC plate
3 数值仿真和分析

 图 4 无限薄平板单站VV极化MLFMA计算RCS分布 Fig.4 Monostatic VV-polarization RCS of the infinitely thin PEC plate by MLFMA algorithm

 图 5 无限薄平板双站VV极化MLFMA计算RCS分布 Fig.5 Bistatic VV-polarization RCS of the infinitely thin PEC plateby MLFMA algorithm

 图 6 双站VV极化RCS结果分布(300 GHz)。角度设置为 ${\theta _{\rm{i}}}$ =15°, ${\varphi _{\rm{i}}}$ =180°, ${\varphi _{\rm{s}}}$ =0°, ${\theta _{\rm{s}}}$ =0°～90°共91个点 Fig.6 Bistatic VV-polarization RCS of the infinitely thin rough PEC plate at 300 GHz. The incident direction is given by ${\theta _{\rm{i}}}$ =15° and ${\varphi _{\rm{i}}}$ =180°. The observation angle is from ${\theta _{\rm{s}}}$ =0° to ${\theta _{\rm{s}}}$ =90° with 91 points, in which ${\varphi _{\rm{s}}}$ =0°
 图 7 双站HH极化RCS结果分布(300 GHz)。角度设置为 ${\theta _{\rm{i}}}$ =15°, ${\varphi _{\rm{i}}}$ =180°, ${\varphi _{\rm{s}}}$ =0°, ${\theta _{\rm{s}}}$ =0°～90°共91个点 Fig.7 Bistatic HH-polarization RCS of the infinitely thin rough PEC plate at 300 GHz. The incident direction is given by ${\theta _{\rm{i}}}$ =15° and ${\varphi _{\rm{i}}}$ =180°. The observation angle is from ${\theta _{\rm{s}}}$ =0° to ${\theta _{\rm{s}}}$ =90° with 91 points, in which ${\varphi _{\rm{s}}}$ =0°
 图 8 双站VV极化RCS结果分布(300 GHz)。角度设置为 ${\theta _{\rm{i}}}$ =15°, ${\varphi _{\rm{i}}}$ =180°, ${\theta _{\rm{s}}}$ =15°, ${\varphi _{\rm{s}}}$ =0°～360°共361个点 Fig.8 Bistatic VV-polarization RCS of the infinitely thin rough PEC plate at 300 GHz. The incident direction is given by ${\theta _{\rm{i}}}$ =15° and ${\varphi _{\rm{i}}}$ =180°. The observation angle is from ${\varphi _{\rm{s}}}$ =0° to ${\varphi _{\rm{s}}}$ =360° with 361 points, in which ${\theta _{\rm{s}}}$ =15°
 图 9 双站HH极化RCS结果分布(300 GHz)。角度设置为 ${\theta _{\rm{i}}}$ =15°, ${\varphi _{\rm{i}}}$ =180°, ${\theta _{\rm{s}}}$ =15°, ${\varphi _{\rm{s}}}$ =0°～360°共361个点 Fig.9 Bistatic HH-polarization RCS of the infinitely thin rough PEC plate at 300 GHz. The incident direction is given by ${\theta _{\rm{i}}}$ =15° and ${\varphi _{\rm{i}}}$ =180°. The observation angle is from ${\varphi _{\rm{s}}}$ =0° to ${\varphi _{\rm{s}}}$ =360° with 361 points, in which ${\theta _{\rm{s}}}$ =15°

 图 10 单站VV极化RCS结果分布(300 GHz)。角度设置为 ${\varphi _{\rm{i}}}$ =0°, ${\theta _{\rm{i}}}$ =0°～90°共91个点 Fig.10 Monostatic VV-polarization RCS of the PEC infinitely thin rough plate at 300 GHz. The observation angle is from ${\theta _{\rm{i}}}$ =0° to ${\theta _{\rm{i}}}$ =90° with 91 points, in which ${\varphi _{\rm{i}}}$ =0°
 图 11 单站HH极化RCS结果分布(300 GHz)。角度设置为 ${\varphi _{\rm{i}}}$ =0°, ${\theta _{\rm{i}}}$ =0°～90°共91个点 Fig.11 Monostatic HH-polarization RCS of the PEC infinitely thin rough plate at 300 GHz. The observation angle is from ${\theta _{\rm{i}}}$ =0° to ${\theta _{\rm{i}}}$ =90° with 91 points, in which ${\varphi _{\rm{i}}}$ =0°
4 小结

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