摘要
介绍了一种宽带双极化星载SAR有源相控阵天线阵,该天线以TR组件和双极化线阵组成的有源线阵为基础,并根据相控阵天线对雷达信号瞬时带宽的限制条件,选择合适的实时延迟子阵,结合结构安装的要求,构成电气独立的模块。在此基础上,根据雷达对天线孔径大小的需要,通过馈电网络激励拓展成大型有源相控阵天线,该天线可以通过波控灵活的控制和网络的合成,实现多极化、波束扫描、波束赋形和多通道等功能。其中对于双极化辐射天线,分别针对微带贴片天线阵和波导缝隙天线进行了分析和研究,并给出了实验验证结果。微带天线阵采用宽带的双层贴片辐射单元和并馈网络实现大带宽要求,两种正交极化模式分别由共面微带线和缝隙耦合来激励,其馈电网络居于开有耦合缝隙接地板的两侧,实现复杂网络空间安排和降低馈线耦合的功能。对于贴片单元的激励,采用对称、反相馈电和分组优化等方法,有效地提高了极化隔离度和极化纯度;而双极化波导缝隙阵中,以脊波导宽边纵缝谐振阵实现垂直极化,波导窄边非倾斜缝隙阵实现水平极化,在每种线阵中都通过分组馈电、过载技术和辐射/馈电波导一体化设计,实现了宽带和压缩横截面的目的。两种形式的天线阵比较,阵面剖面高度相当,微带阵具有宽带、轻质、易于加工和成本低等优势,而波导缝隙阵则具有高效、高隔离度和低交叉极化等性能,但是其缺点是结构复杂、加工难度大和重量大等。
As the civil and military demands for space-borne synthetic Aperture Radar developed, a higherresolution, multi-polarized, multi-band and multi-mode SAR is required. This sparks the interest in the subject of broadband, dual-polarized phased array. A broadband dual-polarized antenna array for spaceborne SAR application is introduced. The array is formed with the active front-end, the RF distribution, and the necessary electronic components for power supply, control and operation. The basic active frontend, named as active subarray module, comprises RF distribution networks and dual-polarized linear arrays each connected with a TR-module, with which a required array can be extended. The dual-polarized microstrip antenna and waveguide slotted antenna array are designed as the radiating candidates of the active array. The dual-polarized stacked patch array, excited with coplanar microstrip for vertical polarization and aperture coupled microstrip for horizontal one, obtains a wide bandwidth, higher degree of isolation and good cross-polarization level. These owe to the stacked patch, corporate feeds, and elements excitation with equal amplitude but out phase method used. For the dual-polarized waveguide slotted antenna, a ridge waveguide longitudinal slotted array is used for vertical polarization and the non-inclined narrow wall slotted array for horizontal one. With the subarray, overload method, and novel waveguide divider used, the waveguide slotted array achieves a broad bandwidth and compact cross section. The microstrip array and waveguide slotted array for X band applications are designed, fabricated and tested, showing a good performance. The comparison between two types of array indicates that the microstrip antenna shows a broadband, low weight and low-cost performance while the slotted array is of low loss, high isolation and very low cross polarization but complex construct, heavy weight and expensive cost.
出处
《遥感技术与应用》
CSCD
2007年第2期166-172,共7页
Remote Sensing Technology and Application
关键词
合成孔径雷达
天线
极化
微带天线
波导缝隙天线
Synthetic Aperture Radar （SAR）, Antenna, Polarization, Microstrip antenna, Waveguide slotted antenna
