الفهرس | Only 14 pages are availabe for public view |
Abstract This thesis addresses the study and design of implantable antennas for wireless biotelemetry applications. The wireless capsule endoscopy (WCE) system requirements are be presented. WCE records images of the human body digestive tract and transmits it wirelessly to the receiving unit. In this thesis a proposed design of a linearly polarized sunflowered with conformal monopole antenna dedicated for wireless in-body capsule endoscopy applications at 2.4 GHz. The designed antenna offers an advantage of very small size equal to radius of capsule dome. Also, a circularly polarized quadfilar or octafilar helical antenna (QFHA or OFHA) investigated for wireless in-body capsule endoscopy applications. The use of a circularly polarized antenna permits a freedom in capsule orientation during endoscopy process. A multi-layered cylindrical model and homogenous cubic model for the human body tissues are studied and compared. The radiation characteristics of the QFHA and OFHA are encapsulated and placed inside the human model. Both the QFHA and the OFHA in capsule module are designed to resonate at 2.4 GHz with an impedance matching bandwidth of 125 MHz. The effect of the capsule orientation on the performance of the endoscopy process is explained. The response of then OFHA with and without capsulation is studied and introduced. The radiation characteristics of the QFHA and OFHA antennas in different cases are fully analyzed and investigated using the finite integral technique and the result compared with that calculated by finite element method. A 4-arm curl antenna at 2.4 GHz is presented. The antenna arms are sequentially fed to enhance the circular polarization characteristics. The antenna is encapsulated and implanted in the human body. The radiation characteristics of the encapsulated 4-arm curl antenna inside the human body are investigated. The orientation of the WCE inside the human body is demonstrated. The performance of the capsule in free-space with the same dimensions is investigated. The effect of capsule orientation during its travel through the digestive tract on the gain and radiation efficiency has been explained. |