胶囊内窥镜天线的宽带小型化理论与技术研究

The wireless capsule endoscopy technology has shown important application and research value in digestive tract treatment, thanks to its convenience, non-invasiveness and little interference to patient's normal life. Due to the capsule endoscopy's strict limitation on space and application requirement on multi-module integration and simultaneous high-speed data transmission, the capsule antenna, as its important component, is in urgent need of wide bandwidth and compactness. Therefore, based on the precise modeling of the digestive contract, this project firstly focuses on the research of conformal antenna which fits the capsule inwall. The antenna is designed on flexible substrate and its radiating area can be extended by utilizing the capsule's complete interior surface. Thus, its bandwidth can be broadened with very little capsule space consumed. Based on the research above, considering the situation of limited frequency spectrum, this project researches on colocation multi-polarization capsule antenna, so that two separate channels can be achieved and the transmission rate and system capacity of the wireless communication system can be greatly enhanced. Through this project, we can finally achieve a capsule endoscopy antenna with miniaturized size and wide bandwidth, boosting the improvement and development of the capsule endoscopy industry.

无线胶囊内窥镜技术因其便捷、无创、不影响患者正常工作等特点，在消化道诊疗中显示出重要的应用与研究价值。其中，由于胶囊内窥镜物理尺寸的严格限制以及对多功能模块集成、实时高速率数据传输的应用要求，作为其重要组成部件的胶囊天线有迫切的宽带小型化需求。因此，在实现对消化道精确建模的基础上，本项目首先研究贴合胶囊内壁的共形天线。天线构建于柔性基底，利用胶囊内壁向三维展开来拓宽口径，从而使天线带宽得以展宽的同时极少地占用胶囊空间。基于上述研究，考虑到有限频谱资源的情形，本项目拟研究共址多极化的胶囊天线，借此获得两路不相关的信道，从而大大提高无线通信系统的传输速率和系统容量。通过本项目的研究，将最终实现具有宽带小型化性能的胶囊内窥镜天线，从而推动胶囊内窥镜的进一步完善与发展。

胶囊天线是胶囊内窥镜系统中无线收发模块的重要组成部分，用于代替传统刚性的内窥镜，负责将采集到的图像数据信息实时传输给外部接收设备，其研究对胶囊内窥镜系统的完善及发展有重要的实际意义和医学价值。项目主要基于人体建模，研究了可植入胶囊天线及可穿戴中继天线两部分内容，最终实现体内信号的远距离传输。主要研究成果有：1、采用微带馈电的槽贴片结构实现了双频带的胶囊天线；2、采用平面结构往胶囊壁上进行柔性延伸，实现了双频性能，其中低频段为线极化，高频段具备圆极化性能；3、引进MIMO技术，在不引进额外去耦合结构的基础上，通过极化分集实现较好隔离度的二单元MIMO共形胶囊天线；4、结合手表外形，引进了金属框结构，研究了刚性的体表可穿戴中继天线，大大提升了可穿戴设备的实用性；5、通过在柔性聚酰亚胺材料上构建蝶形PIFA结构，实现了质量轻、体积小和超宽带性能的可穿戴中继天线。上述研究成果的取得，为植入天线的小型化与远距离高速率数据传输指引了新的方向，对未来的胶囊内窥镜系统乃至植入系统都具有较好的指导意义。