数字阵列天气雷达低副瓣天线设计

为天气雷达设计一维相扫相控阵天线,方位面副瓣低于-30 d B,波束宽度小于1°,俯仰面接收副瓣低于-40 d B。方位面波束采用窄边波导裂缝阵列天线实现,采用全数字T/R组件精确控制幅度和相位,实现低于-40 d B的俯仰面接收副瓣。测试结果表明,副瓣电平与波束宽度指标与理论值吻合较好,满足指标要求。     

A switched pattern radar antenna array

A procedure to design a switched pattern antenna array is developed and demonstrated on a 16- and eight-element array. The variable spacing of elements allows us to reduce the number of switchable elements to a minimum and to reduce the sidelobes of the effective pattern. Based on this design we have built and tested an eight-element prototype array. Measurements demonstrate the feasibility of the pattern switching concept for improved sidelobe performance.     

Wideband microstrip array antenna with sidelobe cancellationchannels

An antenna array for wideband operation (up to 70%) is presented. The structure has low windloading area and consists of parallel printed circuit boards (PCB) with microstrip dipoles, feed network and metal fences placed between the PCBs. The low profile, low weight antenna array forms the main beam and three difference patterns for sidelobe cancellation. Experimental results are compared with calculations for both microstrip dipole and array     

Reduced sidelobe four-beam antenna array fed by modified Butler matrix

A novel four-beam antenna array fed by a modified 4/spl times/8 Butler matrix is proposed. Four 180/spl deg/ directional couplers in conjunction with a 4/spl times/4 Butler matrix are applied to provide a tapered excitation of a linear eight-element switched-beam antenna array. Sidelobes as low as -20 dB for all four beams have been both theoretically and experimentally achieved. A proposed technique of antenna element rotation simplifies the design of a feeding network.     

多输入多输出雷达发射天线低旁瓣设计

多输入多输出(MIMO)雷达发射波形的多样性,为发射方向图设计提供了更多的自由度。针对阵元等功率条件下获得低旁瓣高增益发射波束的问题,提出了一种采用极小极大准则优化设计发射波形相关矩阵的方法,并将该约束优化问题转换为无约束优化问题,便于采用经典迭代法求解。仿真结果表明:采用极小极大准则设计的发射方向图旁瓣区域平坦,最高旁瓣电平接近理论最低值。最后采用循环(CA)算法,获得易于数字阵列系统实现的相位编码信号,使用该相位编码信号得到的实际发射方向图与理论结果匹配良好。     

一种双扼流槽双极化低旁瓣阵列天线

设计了一种新型低副瓣双极化阵列天线,阵列单元采用角锥喇叭,利用探针分层正交馈电实现双极化辐射,利用双扼流槽解决了宽波束降旁瓣的难题.在阵列馈电设计中,利用空气同轴线网络实现泰勒加权降旁瓣设计,同时,利用反相馈电技术改善了极化隔离度和交叉极化.实测结果表明：在工作频带9.5 GHz±500 MHz,回波损耗小于-10 dB,俯仰面、方位面方向图旁瓣电平小于-16 dB,极化端口隔离度小于-30 dB,交叉极化电平小于-35 dB.     

一种空气同轴馈电的X波段低副瓣阵列天线

设计了一种应用于雷达系统中的低成本低副瓣阵列天线, 该天线阵包含256个辐射单元, 由四个64单元的子阵组成, 采用波导合成网络进行功率合成.天线单元采用空气同轴馈电的角锥喇叭, 空气同轴馈线内外导体呈方型结构, 其终端为短路馈电方式, 实现了内导体的自支撑设计和较低的传输损耗, 并依据综合幅度分布采用若干数量的不等功分器进行低副瓣设计.测试结果表明, 小于2的驻波带宽为0.5 GHz, 相对带宽为7.5%.另外, 中心频率的增益为30 dB, 增益大于29.5 dB的带宽为0.2 GHz, E面和H面的旁瓣电平为28.5 dB和29 dB.     

THE LIMITATION OF MUTUAL IMPEDANCE PRECISION TO THE SIDELOBE LEVEL OF ARRAY ANTENNA

Accurate mutual coupling correction is necessary for an array antenna to reach ultra-low sidelobe level.If the mutual impedance or mutual coupling coefficient matrix of an array isperfectly known,theoretically,one can compensate the effects of mutual coupling completelyand realize the desired low sidelobe level.However,the mutual impedance matrix obtainedwhether by calculation or by measurement has limited precision,which limits the effectiveness ofcompensation.This paper deals with the requirements on the precision of mutual impedance forcompensation in ultra-low sidelobe array antennas.The relationship between mutual impedanceerrors and the amplitude and phase errors of an array is derived,by which the relationship betweenthe mutual impedance errors and the sidelobe level is obtained.     

多输入多输出雷达低旁瓣发射方向图优化算法

提出了一种基于波束域加权的低旁瓣方向图设计方法。综合考虑方向图匹配性能和发射阵元等功率作为约束条件,建立低旁瓣发射方向图优化模型,采用半正定松弛技术将优化模型转化为凸优化问题;对波束加权矩阵施加对偶约束,使得接收信号满足旋转不变性;利用高斯随机化方法对波束加权矩阵进行求解,得到原优化问题的最优解。仿真结果表明,算法能够保持期望主瓣形状并有效降低方向图旁瓣,提高到达角(DOA)的估计精确度和角度分辨力。     

随机误差对模块化阵列天线副瓣的影响

推导了相位误差、单元位置误差和子阵位置误差的取值范围与模块化阵列天线副瓣累积概率的关系,以及单元位置误差、子阵位置误差与整体位置误差的关系.通过实例说明,激励幅相误差、单元位置误差和子阵位置误差,对实现超低副瓣都是至关重要的.     

L波段双脊裂缝波导低副瓣阵列天线的设计

设计了一种L波段双脊波导裂缝阵列天线。该天线具有好的频率响应特性,实现了低副瓣,水平垂直两个面的交叉极化得到了有效抑制。由于馈电双脊波导的截面尺寸大幅度减小,使得这项研究将有很好的应用前景。     

极化情况下高功率微波稀布阵计算模型

建立了考虑极化情况下高功率微波稀布阵合成场的计算模型,分析了阵列合成场大小与极化及阵元初相位关系。极化方向相同时,二元线阵场分布为明暗相间的条纹,三元面阵场分布为网状结构。阵元极化方向及阵元初相位共同影响合成场的叠加效果,阵元的极化决定阵列合成场的最大值,阵元初相位在此基础上对阵列叠加效果进一步调节。对于二元线阵,极化方向夹角越小,合成叠加效率越高;对三元以上的多元面阵,其极化方向组合方式复杂,可通过阵元位置和目标位置模拟阵列合成场的叠加效率,三元稀布面阵的合成场强归一化最大值在2.22~2.43之间,与理想合成场最大值3有一定的差距。该模型提高了稀布阵列合成场强的计算准确度,对阵列高功率微波进行天线阵列设计,进一步提升目标区域的功率密度是一种比较有效的方法。     

激光相控阵与微波相控阵发射天线技术体制的比较

借鉴微波相控阵雷达技术,有的放矢加快探测型激光相控阵雷达的技术发展与应用,从仿学微波相控阵雷达发射天线基础知识入手,提出微波相控阵雷达发射天线与光纤激光相控阵发射天线可比较的部分技术参数;分析了光纤激光相控阵发射天线的技术要点与潜在能力,并立足现有研发水平对其系统功能与规模进行了预测;尝试对光纤激光相控阵与微波相控阵天线的技术特点与面临主要问题进行了论述;提出两者体系内互相配置,不仅有助于提高微波相控阵雷达在复杂电磁环境下对中近程高速、隐身和多目标的探测、识别与定位能力;同时也可适当减少激光相控阵对目标大范围区域搜索的压力的观点。     

Alternative approach to designing array pattern with controlled mean-square sidelobe level

A more general and efficient approach for designing array patterns with a controlled mean-square sidelobe level is presented. It is shown that the approach presented by Ng (see ibid., vol.26, p.337-9, 1990) can be considered as a limiting solution to the quadratic constrained optimisation problem presented in this Letter. Numerical results showed that under high interference-to-white noise ratio conditions, the new approach performs better, on average, than the Chebyshev synthesis technique.<>     

非均匀线阵多输入多输出雷达成像旁瓣抑方法

针对非均匀线阵多输入多输出(Multiple Input Multiple Output,MIMO)雷达空间采样率低、成像旁瓣较高的问题,提出了一种基于阵列内插技术的非均匀线阵MIMO雷达成像旁瓣抑制方法. 对匹配滤波后MIMO雷达形成的非均匀等效阵列进行虚拟内插处理,将其变换为均匀线阵,在此基础上,再采用反向投影(Back Projection,BP)算法进行成像. 理论分析和仿真结果表明：所提方法有效地降低了非均匀线阵MIMO雷达的旁瓣水平,提高了成像质量.      

Wide-frequency-band radar array antenna system with suppressed grating lobes

When array antennas are used for wide-frequency operation a difficulty with grating lobes is encountered at the upper frequency end of the operating band. This paper points out that the use of arrays for transmission and reception with different interelement spacings can be used to extend the operating frequency band in a radar system. The principle of transmitting-receiving arrays with different illuminations was used by Mattingly [2] to lower the sidelobe level of a radar array antenna. Birge [3] used it to reduce the number of elements in an array while preserving the resolution. The same principle is used in this paper to extend the operating frequency bandwidth of a radar antenna system. Relationships for an optimized radar array antenna system are derived. The criterion for optimization is the maximum bandwidth with a given total number of elements. It is shown that in an optimized system the number of elements in one array antenna is one greater than in the other, and the ratio of interelement spacings is inversely proportional to the square of the number of elements in the respective arrays. Based on these conditions, a functionkis computed and tabulated. This function determines the number of grating lobes permissible in the specified angular sector, without overlap, as a function of the number of elements in the two arrays. An application to a high frequency (HF) ionospheric radar antenna system, now under construction, is used as an illustration of the principles outlined in the paper.     

Cramer-Rao bound analysis for active array with antenna switching

An active radar array with antenna switching provides information on the direction, velocity and range of multiple-targets, in which the receiving antennas are switched to the single receiving channel periodically. The Cramer-Rao bound expressions for estimating the movement parameters using the radar system are derived.     

应用于24GHz物位雷达的微带阵列天线设计

为了提高24 GHz物位雷达系统的精度和抗干扰能力,设计并制作了一款高增益、低副瓣、易集成的微带阵列天线。为了抑制天线的副瓣电平,该天线各阵元间的电流采用同相不等幅分布设计;同时,采用两种不同馈线的单元和串并联混合馈电网络,降低了馈电网络的设计难度。实测结果表明,该阵列天线的带宽为690 MHz(23.77~24.46 GHz),最大增益达到20.1 dBi,E面和H面的副瓣电平分别为-20.7 dB和-19.3 dB。该阵列天线结构紧凑、可靠性高,可用于24 GHz物位雷达系统。     

Realizable method of pattern synthesis for array antenna

The problem of realization of an arbitrary current distribution on an broadside array antenna derived from the theory of pattern synthesis is treated and some practical methods are proposed. In these methods, the input voltage of each antenna is transformed by a reactive transformer to take the required value. In one of the methods, experiments to yield Chebyshev patterns were performed and satisfactory results were obtained.