一款具有稳定扫描波束分辨率的宽视角相控阵天线

A Wide-Angular Phased Array Antenna with Stable Scanning Beam Resolution

基于自适应稀疏阵的结构,提出了一种具有宽视角与稳定扫描波束分辨率性能的相控阵天线。阵列单元是可以在相同谐振频率下实现TM;和TM;两种模式共同工作的单激励圆环贴片天线,其具有140°的半功率波束宽度,这种宽波束辐射效果能够较好地拓展相控阵天线的扫描范围。基于此单元构建了一个35元线阵,对其波束扫描分析发现在限定增益波动小于2 dB的条件下阵列扫描范围可以达到-70°~+70°,但主瓣波束宽度随着扫描角度的增加而增大。为解决这个问题,引入了自适应稀疏阵的概念,并采用基于互耦补偿矩阵的迭代快速傅里叶变换(Iterative Fast Fourier Transform,IFFT)技术进行自适应稀疏阵的优化设计。结果表明,所提出的基于自适应稀疏阵结构的35单元相控阵天线在-60°~+60°扫描范围内增益波动始终小于1.5 dB,波束宽度波动小于1°,且峰值旁瓣电平基本保持在-20 dB以下。相较于均匀周期阵列,所提出的自适应稀疏相控阵天线能够在实现低旁瓣宽视角扫描的同时,有效提高天线在宽角度范围内扫描波束分辨率的稳定性。

A phased array antenna with wide-angular and stable scanning beam resolution performance is proposed based on the adaptively thinned arrays structure in this paper.The designed element antenna is a single-fed ring patch which can simultaneously operate TM;and TM;modes at the same resonant frequency,and its half-power beam-width is 140°.Such a wide-beam radiation can efficiently broaden the scanning range of its phased array.Based on the designed element,a 35-element linear array is constructed and simulated.The designed array antenna can achieve a scanning range of-70°to+70°with its gain fluctuation less than 2 dB.However,the main lobe beam-width increases with the scanning angle.To solve this problem,the concept of the adaptively thinned arrays is introduced,and the iterative fast Fourier transform(IFFT)technique based on the mutual coupling compensation matrix is used to optimize the design of the adaptively thinned array.The results show that the proposed 35-element adaptively thinned phased array can achieve a scanning range of-60°to+60°.Besides,the array has its gain fluctuation of less than 1.5 dB,the beam-width fluctuation of less than 1°and the peak side-lobe level of less than-20 dB.Compared with uniform periodic array,the proposed design effectively improves the stability of the scanning beam resolution in a wide angle range while realizing the low side-lobe and wide-angular scanning.