Enabling Seamless Wireless Power Delivery in Dynamic Environments

Sample, Alanson P.; Waters, Benjamin H.; Wisdom, Scott; Smith, Joshua R.

doi:10.1109/jproc.2013.2252453

Cited by 170 publications

(91 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In [8], the authors present multiple concepts for multi-hop wireless energy transfer (such as store and forward vs. directly single hop transfer) and derive the efficiency of each method using magnetically coupled resonators for wireless power transfer demonstrated in [13]. However, this non-radiative transfer is shown to work up to 2 m and requires perfectly aligned coils of 25 cm radius among the source and receiver nodes.…”

Section: B Sensor Network With Wireless Energy Transfermentioning

confidence: 99%

RF-MAC: A Medium Access Control Protocol for Re-Chargeable Sensor Networks Powered by Wireless Energy Harvesting

Naderi

Nintanavongsa

Chowdhury

2014

IEEE Trans. Wireless Commun.

162

View full text Add to dashboard Cite

Abstract-Wireless charging through directed radio frequency (RF) waves is an emerging technology that can be used to replenish the battery of a sensor node, albeit at the cost of data communication in the network. This tradeoff between energy transfer and communication functions requires a fresh perspective on medium access control (MAC) protocol design for appropriately sharing the channel. Through an experimental study, we demonstrate how the placement, the chosen frequency, and number of the RF energy transmitters impact the sensor charging time. These studies are then used to design a MAC protocol called RF-MAC that optimizes energy delivery to sensor nodes, while minimizing disruption to data communication. In the course of the protocol design, we describe mechanisms for (i) setting the maximum energy charging threshold, (ii) selecting specific transmitters based on the collective impact on charging time, (iii) requesting and granting energy transfer requests, and (iv) evaluating the respective priorities of data communication and energy transfer. To the best of our knowledge, this is the first distributed MAC protocol for RF energy harvesting sensors, and through a combination of experimentation and simulation studies, we observe 300% maximum network throughput improvement over the classical modified unslotted CSMA MAC protocol.

show abstract

Section: B Sensor Network With Wireless Energy Transfermentioning

confidence: 99%

RF-MAC: A Medium Access Control Protocol for Re-Chargeable Sensor Networks Powered by Wireless Energy Harvesting

Naderi

Nintanavongsa

Chowdhury

2014

IEEE Trans. Wireless Commun.

162

View full text Add to dashboard Cite

show abstract

“…Typical experimental implementations to decrease the channel variation make use of additional impedance matching networks attached to the transfer system (Beh et al, 2013;Waters et al, 2012;Sample et al, 2013) or several switchable coupling coils (Kim et al, 2012). Especially (Sample et al, 2013) shows, that this impedance matching network adds additional resonant peaks in between the resonators main peaks, thus providing the possibility to transfer energy at a fixed frequency. Due to the fact that the matching networks consist of switchable elements, it is obvious that the system performance is optimized only for discrete distances dependent on the number of possible switch combinations.…”

Section: Channel Adaptionmentioning

confidence: 99%

Investigations and system design for simultaneous energy and data transmission through inductively coupled resonances

Schmidt¹,

Fuentes²,

Buchholz³

2015

Adv. Radio Sci.

View full text Add to dashboard Cite

Abstract. Wireless Power Transfer (WPT) with simultaneous data transmission through coupled magnetic resonators is investigated in this paper. The development of this system is dedicated to serve as a basis for applications in the field of Ambient Assisted Living (AAL), for example tracking vital parameters remotely, charge and control sensors and so on. Due to these different scenarios we consider, it is important to have a system which is reliable under the circumstance of changing positioning of the receiving device. State of the art radio systems would be able to handle this. Nevertheless, energy harvesting from far field sources is not sufficient to power the devices additionally on mid-range distances. For this reason, coupled magnetic resonant circuits are proposed as a promising alternative, although suffering from more complex positioning dependency.Based on measurements on a simple prototype system, an equivalent circuit description is used to model the transmission system dependent on different transmission distances and impedance matching conditions. Additionally, the simulation model is used to extract system parameters such as coupling coefficients, coil resistance and self-capacitance, which cannot be calculated in a simple and reliable way.Furthermore, a mathematical channel model based on the schematic model has been built in MATLAB © . It is used to point out the problems occurring in a transmission system with variable transmission distance, especially the change of the passband's centre frequency and its bandwidth. Existing solutions dealing with this distance dependent behaviour, namely the change of the transmission frequency dependent on distance and the addition of losses to the resonators to increase the bandwidth, are considered as not inventive. First, changing the transmission frequency increases the complexity in the data transmission system and would use a disproportional total bandwidth compared to the actually available bandwidth. Additionally, adding losses causes a decrease in the energy transmission efficiency.Based on these facts, we consider a system that changes the channel itself by tuning the resonant coils in a way that the passband is always at a fixed frequency. This would overcome the previously described issues, and additionally could allow for the possibility to run several independent transmission systems in parallel without disturbing each other.

show abstract

“…Their design employs a variety of techniques, including quality-factor enhancements [16], adaptive tuning [19], and relay coils [18]. Near-perfect efficiency (> 70%) has been demonstrated across distances comparable to the dimensions of the coils [16][17][18].…”

Section: Near-field Systemsmentioning

confidence: 99%

“…In the weak coupling regime, it can be shown that the impedance-matching conditions are simply ω = ω S = ω C and γ L = γ C , where ω is the operating frequency and γ C the rate of energy loss at the receiver structure [26]. In the strong-coupling regime, the matching conditions differ by a correcting term dependent on the coupling strength due to mode-splitting [19]. For high energy-transfer performance, it is critical for the parameters of the structures and the load to satisfy these conditions.…”

Section: Coupled Structuresmentioning

confidence: 99%

ENERGY TRANSFER FOR IMPLANTABLE ELECTRONICS IN THE ELECTROMAGNETIC MIDFIELD (Invited Paper)

Ho¹,

Poon²

2014

PIER

View full text Add to dashboard Cite

Abstract-The wireless transfer of electromagnetic energy into the human body could power medical devices and enable new ways to treat various disorders. To control energy transfer, metal structures are used to generate and manipulate radio-frequency electromagnetic fields. Most systems for transfer across the biological tissue operate in the quasi-static limit, but operation beyond this regime could afford new powering capabilities. This review discusses some recent developments in the design and implementation of systems operating in the electromagnetic midfield, where transfer exploits wave-like fields in the body.

show abstract

Enabling Seamless Wireless Power Delivery in Dynamic Environments

Cited by 170 publications

References 24 publications

RF-MAC: A Medium Access Control Protocol for Re-Chargeable Sensor Networks Powered by Wireless Energy Harvesting

RF-MAC: A Medium Access Control Protocol for Re-Chargeable Sensor Networks Powered by Wireless Energy Harvesting

Investigations and system design for simultaneous energy and data transmission through inductively coupled resonances

ENERGY TRANSFER FOR IMPLANTABLE ELECTRONICS IN THE ELECTROMAGNETIC MIDFIELD (Invited Paper)

Contact Info

Product

Resources

About