In this article, the first-ever dual-circular-polarized wideband conformal endoscopic antenna is designed at the medical implant communication service band (402 MHz) and industrial, scientific, and medical bands (915 MHz and 2.4 GHz). The proposed antenna with a small footprint of 8 mm3 (32 mm $\times 10$ mm $\times0.025$ mm) is printed on flexible polyamide and wrapped onto the inner wall of the capsule to spare the space for the capsule integrated components. For evaluation of the antenna’s performance within a full-package endoscopic device, a homogeneous muscle box and realistic Duke human phantoms were used. For measurement, the fabricated antenna is enclosed inside a 3-D-printed capsule along with the endoscopic system, and the enclosed system is waterproofed. The S-parameters and radiation patterns are measured in a saline-filled American Society for Testing and Materials (ASTM) model and a minced-pork phantom. The measured impedance bandwidths and gains at 402 MHz, 915 MHz, and 2.4 GHz are 236.2%, 104%, and 55.4% and −29.71, −28.7, and −20.8 dBi, respectively. The measured axial-ratio bandwidths are 45.9% and 21.3% at 915 MHz and 2.4 GHz, respectively. Furthermore, the link budget is numerically analyzed and measured via real-time telemetry using software-defined radios. The proposed antenna complies well with the human safety standards and satisfies the range and high data-rate requirements.

中文翻译：

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具有宽带特性和无线生物遥测链路特性的双圆极化内窥镜天线

在本文中，首个双圆极化宽带共形内窥镜天线设计用于医疗植入通信服务频段 (402 MHz) 和工业、科学和医疗频段 (915 MHz 和 2.4 GHz)。8 mm3 小尺寸天线（32 mm $\times 10 $ mm $\times0.025 $ mm）印刷在柔性聚酰胺上并包裹在胶囊的内壁上，为胶囊集成组件腾出空间. 为了评估全封装内窥镜设备中天线的性能，使用了均质肌肉箱和逼真的杜克人体模型。为了进行测量，制造的天线与内窥镜系统一起被封闭在一个 3D 打印的胶囊内，并且封闭系统是防水的。S 参数和辐射模式在充满盐水的美国材料与试验协会 (ASTM) 模型和猪肉糜模型中进行测量。在 402 MHz、915 MHz 和 2.4 GHz 下测得的阻抗带宽和增益分别为 236.2%、104% 和 55.4% 以及 -29.71、-28.7 和 -20.8 dBi。在 915 MHz 和 2.4 GHz 下，测得的轴向比带宽分别为 45.9% 和 21.3%。此外，使用软件定义无线电通过实时遥测对链路预算进行数值分析和测量。所提出的天线符合人体安全标准，满足范围和高数据速率要求。分别。在 915 MHz 和 2.4 GHz 下，测得的轴向比带宽分别为 45.9% 和 21.3%。此外，使用软件定义无线电通过实时遥测对链路预算进行数值分析和测量。所提出的天线符合人体安全标准，满足范围和高数据速率要求。分别。在 915 MHz 和 2.4 GHz 下，测得的轴向比带宽分别为 45.9% 和 21.3%。此外，使用软件定义无线电通过实时遥测对链路预算进行数值分析和测量。所提出的天线符合人体安全标准，满足范围和高数据速率要求。