Field Inductive Coupling Research Articles

Vagus nerve stimulation using a miniaturized wirelessly powered stimulator in pigs

Neuromodulation of peripheral nerves has been clinically used for a wide range of indications. Wireless and batteryless stimulators offer important capabilities such as no need for reoperation, and extended life compared to their wired counterparts. However, there are challenging trade-offs between the device size and its operating range, which can limit their use. This study aimed to examine the functionality of newly designed wirelessly powered and controlled implants in vagus nerve stimulation for pigs. The implant used near field inductive coupling at 13.56 MHz industrial, scientific, and medical band to harvest power from an external coil. The circular implant had a diameter of 13 mm and weighed 483 mg with cuff electrodes. The efficiency of the inductive link and robustness to distance and misalignment were optimized. As a result, the specific absorption rate was orders of magnitude lower than the safety limit, and the stimulation can be performed using only 0.1 W of external power. For the first time, wireless and batteryless VNS with more than 5 cm operation range was demonstrated in pigs. A total of 84 vagus nerve stimulations (10 s each) have been performed in three adult pigs. In a quantitative comparison of the effectiveness of VNS devices, the efficiency of systems on reducing heart rate was similar in both conventional (75%) and wireless (78.5%) systems. The pulse width and frequency of the stimulation were swept on both systems, and the response for physiological markers was drawn. The results were easily reproducible, and methods used in this study can serve as a basis for future wirelessly powered implants.

A capsule robot powered by wireless power transmission: Design of its receiving coil

Wireless power transmission based on near field inductive coupling is a promising solution to power a freely moving capsule robot for a long duration. Existing multi-dimensional receiving coils are normally solid cylinders, which increase the total length of the capsule robot. We propose using a hollow-cylinder like three-dimensional receiving coil to avoid increasing the length and to improve space utilization. This receiving coil consists of a circular coil, two pairs of planar coils, and a hollow-cylinder like ferrite core. Taking into consideration human safety and the limited available space in the capsule robot, the number of turns and the wire diameter of the receiving coil, as well as the transmission frequency, have been optimized. This receiving coil could output electric power ranging from 206mW to 1130mW; integrated to an inchworm-like capsule robot, it could successfully power the robot to travel through the ex-vivo intestinal tract and capture satisfactory intestinal videos for diagnosis.

Impact of RFID and Xbee Communication Network on Supply Chain Management

Every industry, organization or individual needs to be minimize their expenditure, time and fatigue and maximize their profit in supply chain. These goals can be achieved through automation by using Radio Frequency Identification (RFID) and Zigbee wireless communication technologies, which is easily available in the market. Basically RFID technology is used for automatically tracking, locating or identifying the entities. It can easily integrate with low cost low power consumption Xbee (Zigbee) device, which is used to increase the communication range by large number of node deployment. RFID-Xbee network integrates with Laboratory Virtual Instrument Engineering Workbench (LabVIEW) Graphical User Interface (GUI), which gives real time information of supply chain at single control panel. The integrated communication model proves the near field inductive coupling and can be used in supermarket for item pricing, office automation, security system, and car parking. This system confirms the concept of real-time locating system (RTLS) in an indoor environment. The impact of RFID and Xbee network communication model enhance the read range of RFID reader, so that out of range items can be tracked easily without additional RFID readers. The benefit of this system is to maximize profit, reduce human intervention and minimize waste.

Evaluation of Coupling Factor in RF Inductively Coupled Systems

This work presents an approach for the measurement of mutual inductance on near field inductive coupling. The mutual inductance between inductive circuits allows the simulation of energy transfer from reader to tag, that can be used in RFID and powerless implantable devices. It also allows one to predict the maximum voltage in the tag of the radio-frequency system. Keywords—RFID, Inductive Coupling, Energy Transfer, Implantable Device