一种宽角扫描紧耦合阵列天线单元设计

Design of a wide-angle scanning tightly coupled dipole array element

提出一种新型紧耦合偶极子阵列天线单元,并结合等效电路对天线参数进行分析与优化。引入频率选择表面置于天线口径上方,取代传统的电介质板,用以改善宽角扫描时阻抗变换。巴伦采用微带线到共面平行双线过渡结构,实现平衡馈电及阻抗变换。仿真结果表明,该阵列能够实现3倍频(2~6 GHz)E面80°、H面45°的波束扫描,且在扫描范围内有源驻波比均小于3。仿真得到的阵列法向交叉极化隔离度保持在25 dB,由于阻性FSS的损耗,天线增益有所下降。该天线结构简单紧凑,易于加工制作,实现了紧耦合阵列的小型化。

The paper proposes a novel tightly coupled dipole array antenna element design,and combines the equivalent circuit to analyze and optimize antenna parameters.The design introduces frequency selective surface placed above the antenna aperture to replace the traditional dielectric superstrate for wideband and wide-angle impedance matching.The balun employs microstrip to coplanar parallel two-wire transition structure to achieve balanced feed and impedance transformation.A prototype is simulated and the results show that the design provides a 3∶1(from 2 GHz to 6 GHz)bandwidth while scanning to 80°in E-plane and scanning to 45°in H-plane,with an active VSWR<3.Besides,the cross-polarization isolation of the array at broadside is kept at 25 dB,but the antenna gain is reduced due to the loss of the resistive FSS.The antenna has a simple and compact structure,easy to fabricate,thus realizes miniaturization of a tightly coupled array.