Emerging Transmitting Antenna for Implant Communications

Description

Applying wireless technologies in biomedicine for implant communications has become popular recently. Implantable devices including micro camera, pH sensor, electro sensor, and pressure sensor help to identify a recessive condition, disease, or an injury by evaluating the symptoms and signs presented by a patient. Many researches put efforts to develop implantable devices in capsule size or even smaller for surgery with minimal invasion. However, there is a trade-off between the size of device and the capacity of energy storage. A larger size of battery provides more durable electric energy for device operations but takes up enormous volume. Removal of the battery is the most effective way to miniaturize the size of those implants; nonetheless, an external wireless power supply is required. Conventional techniques of wireless power transfer (WPT) for medical implants employ loop antennas to induce voltage at the receiving coil of the implant. This technique limits the operation in a near-field range and has a drawback in sensitivity of the implant orientation. If the implant moves slightly far away from the transmitting antenna, the link efficiency of power delivery weakens. Similarly, if there is a mismatch between the implant orientation and the antenna, the link efficiency reduces significantly. These are the fundamental constraints of loop antennas for wireless powering of implants.In this project, we plan to develop new transmitting antennas for WPT for implant communications. Firstly, we will investigate a mid-field WPT. With the introduction of mid-field operation, the distance of power transfer between the transmitting antenna and the receiver can be increased. Secondly, we will propose circularly polarized (CP) wave propagations for enhancing the link quality. The link efficiency achieves a noticeable advantage for an arbitrariness of implant orientations when the CP wave is used. We will design wideband CP transmitting antennas for improving the link quality of the system. Thirdly, we will carry out a study of tissue loadings effect on the transmitting antennas. Finally, we will design two array structures for enlarging the effective communicating coverage of the implants and power focusing delivery. The ultimate goal of this project is to devote an emerging antenna technology to biomedical application, particularly in implant communications. The proposed techniques contribute to the WPT that enables medical implant communications to be more robust, stable and reliable.