A compact multiple input multiple output (MIMO) antenna operating at 2.45 GHz industrial scientific and medical band is presented for wearable devices. Open-end slotting is used to miniaturize the antenna dimensions. Inverted U-shaped ground stub is incorporated to reduce mutual coupling. On-body performance is analyzed on a three-layered equivalent tissue phantom model. The wide bandwidth of 300 MHz and port isolation of 30 dB are obtained from measured results. The antenna shows the efficiency of 40% and directivity of 4.56 dBi when placed at a gap of “s” = 4 mm from the body. Broadside radiation pattern and low specific absorption rate make the antenna suitable for on-body communication. Further, diversity performance is measured in terms of envelope correlation coefficient (ECC), diversity gain (DG), and channel capacity loss (CCL). The value of ECC is 0.025, DG is 9.98 dB, and CCL is 0.12 bits/s/Hz at 2.45 GHz. Antenna robustness is examined by bending the structure at different radii along the x-axis and y-axis. Performance of the proposed structure is reliable with structural deformation.

中文翻译：

---

可穿戴式 MIMO 天线设计采用倒 U 形接地短截线以增强分集性能

为可穿戴设备展示了一种工作在 2.45 GHz 工业科学和医疗频段的紧凑型多输入多输出 (MIMO) 天线。开口开槽用于缩小天线尺寸。采用倒 U 形接地短截线以减少相互耦合。在三层等效组织体模模型上分析了身体性能。从测量结果中获得了 300 MHz 的宽带宽和 30 dB 的端口隔离度。当放置在“s” = 距离身体 4 毫米。宽边辐射方向图和低比吸收率使天线适用于人体通信。此外，分集性能是根据包络相关系数 (ECC)、分集增益 (DG) 和信道容量损失 (CCL) 来衡量的。ECC 的值为 0.025，DG 为 9.98 dB，CCL 在 2.45 GHz 时为 0.12 bits/s/Hz。通过沿不同半径弯曲结构来检查天线的鲁棒性X-轴和是的-轴。所提出的结构的性能是可靠的结构变形。