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An Overview of Frequency Diverse Array Radar Technology
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摘要: 频率分集阵(Frequency Diverse Array, FDA)雷达不同天线单元的发射载频存在微小的差异，从而带来了发射方向图距离角度时间依赖的特性，这一特性提供了FDA雷达新的信息和信号处理灵活度，也带了新的技术问题。该文综述了FDA天线技术及雷达应用的相关研究进展，并重点从雷达系统理论与工程应用的角度，着重分析了相干FDA雷达和正交FDA雷达两种体制的技术特点，指出FDA雷达在抗干扰、抗模糊中的应用优势，梳理了FDA雷达技术的难点和研究方向。Abstract: The carrier frequencies of array elements in a Frequency Diverse Array (FDA) radar are slightly distinguished, leading to a range-angle-time-dependent transmit beampattern. Thus, an FDA radar carries additional information in a certain range and provides more flexibility in signal processing and new technical issues. FDA is covered by scope of the general waveform diversity concept. This paper overviews the state-of-the-art FDA technology and its radar applications. From the viewpoint of the general radar system theory, we mainly introduce the coherent FDA and orthogonal FDA frameworks. The orthogonal FDA is also referred to as Multiple-Input Multiple-Output (MIMO) radar using FDA or FDA-MIMO radar. Key applications in anti-jamming and issues related with range ambiguity are addressed. We also outline the challenges in FDA radar applications and several interesting research topics.
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图 1 电场强度随角度和时间的变化关系，R=3 km
Figure 1. Electric field intensity with respect to angle and time, R=3 km
图 2 电场强度随距离和角度的变化关系，R=[1.5 km, 4.5 km]
Figure 2. Electric field intensity with respect to range and angle, R=[1.5 km, 4.5 km]
图 3 不同角度方向对应的电场强度，R=3 km
Figure 3. Electric field intensity in different angles/directions, R=3 km
图 4 相控阵和FDA的辐射电场能量分布图的传播示意图
Figure 4. Radiated power distribution and propagation of electric field
图 5 脉冲体制发射-接收联合波束形成，Tp=1/
$\Delta $ fFigure 5. Joint tranmit-receive beamforming with pulsed FDA, Tp=1/
$\Delta $ f
图 6 脉冲体制发射-接收联合波束形成，Tp=1/(2
$\Delta $ f)Figure 6. Joint tranmit-receive beamforming with pulsed FDA, Tp=1/(2
$\Delta $ f)
图 10 运动平台FDA-MIMO雷达发射-接收2维域的功率谱分布示意图
Figure 10. Spectra distribution of signal in transmit-receive two-dimensional domain with FDA-MIMO radar mounted on moving platform
图 12 干扰机真实目标和假目标在发射-接收2维空间频率域的分布
Figure 12. Distribution of True and false targets in transmit-receive two-dimensional spatial frequency domain
表 1 3种体制发射方向图相关特性比较
Table 1. Comparion of characters related to transmit beampatterns of phased array, MIMO, and FDA
阵列体制 不同方向的时域响应 方向图的距离依赖性 发射方向图主瓣 天线发射增益 相控阵 各向同性 距离无关 稳定 M2 经典MIMO 各向异性 随距离变化，无规律 无 M FDA 各向异性 随距离变化，有规律 自动扫描 M 
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