ABSTRACT

A small-size broadband circularly polarized (CP) two-element multiple-input–multiple-output (MIMO) slot antenna with a very low envelope correlation coefficient (ECC) is proposed for ultra-wideband (UWB) applications. Broadband circular polarization is attained by embedding the identical pair of spiral slots, rectangular slot, and grounded-L stub on the I-shaped slot antenna. Isolation is achieved through embedding two different slots between mirrored CP square slot antenna elements. The proposed MIMO antenna provides 58.82% (4.8–8.8 GHz) 3-dB axial ratio bandwidth (ARBW), 138.32% (3.17–17.39 GHz) impedance bandwidth (IBW), and more than 16 dB port isolation over the operating band. The MIMO slot antenna size is 40 × 20 mm² with a measured peak gain of about 4.41 dBi and efficiency more than 70%. The diversity performance is computed and presented in detail.

摘要

针对超宽带 (UWB) 应用提出了一种具有极低包络相关系数 (ECC) 的小尺寸宽带圆极化 (CP) 二单元多输入多输出 (MIMO) 缝隙天线。宽带圆极化是通过在 I 形缝隙天线上嵌入相同的一对螺旋缝隙、矩形缝隙和接地的 L 短截线来实现的。通过在镜像 CP 方形缝隙天线元件之间嵌入两个不同的缝隙来实现隔离。拟议的 MIMO 天线在工作频段上提供 58.82% (4.8–8.8 GHz) 3 dB 轴比带宽 (ARBW)、138.32% (3.17–17.39 GHz) 阻抗带宽 (IBW) 和超过 16 dB 的端口隔离。MIMO 缝隙天线尺寸为 40 × 20 mm ²测得的峰值增益约为 4.41 dBi，效率超过 70%。计算并详细呈现多样性性能。