Energy efficient anti-collision algorithm for the RFID networks

Energy efficiency is crucial for radio frequency identification (RFID) systems as the readers are often battery operated. The main source of the energy wastage is the collision which happens when tags access the communication medium at the same time. Thus, an efficient anti-collision protocol could minimize the energy wastage and prolong the lifetime of the RFID systems. In this regard, EPCGlobal-Class1-Generation2 (EPC-C1G2) protocol is currently being used in the commercial RFID readers to provide fast tag identification through efficient collision arbitration using the Q algorithm. However, this protocol requires a lot of control message overheads for its operation. Thus, a reinforcement learning based anti-collision protocol (RL-DFSA) is proposed to provide better time system efficiency while being energy efficient through the minimization of control message overheads. The proposed RL-DFSA was evaluated through extensive simulations and compared with the variants of EPC-Class 1 Generation 2 algorithms that are currently being used in the commercial readers. The results show conclusively that the proposed RL-DFSA performs identically to the very efficient EPC-C1G2 protocol in terms of time system efficiency but readily outperforms the compared protocol in the number of control message overhead required for the operation

State-of-the-Art Developments of Acoustic Energy Transfer

Acoustic energy transfer (AET) technology has drawn significant industrial attention recently. This paper presents the reviews of the existing AETs sequentially, preferably, from the early stage. From the review, it is evident that, among all the classes of wireless energy transfer, AET is the safest technology to adopt. Thus, it is highly recommended for sensitive area and devices, especially implantable devices. Though, the efficiency for relatively long distances (i.e., >30 mm) is less than that of inductive or capacitive power transfer; however, the trade-off between safety considerations and performances is highly suitable and better than others. From the presented statistics, it is evident that AET is capable of transmitting 1.068 kW and 5.4 W of energy through wall and in-body medium (implants), respectively. Progressively, the AET efficiency can reach up to 88% in extension to 8.6 m separation distance which is even superior to that of inductive and capacitive power transfer

Negative index metamaterial-based frequency-reconfigurable textile cpw antenna for microwave imaging of breast cancer

In this paper, we report the design and development of a metamaterial (MTM)-based di�rectional coplanar waveguide (CPW)-fed reconfigurable textile antenna using radiofrequency (RF) varactor diodes for microwave breast imaging. Both simulation and measurement results of the proposed MTM-based CPW-fed reconfigurable textile antenna revealed a continuous frequency re�configuration to a distinct frequency band between 2.42 GHz and 3.2 GHz with a frequency ratio of 2.33:1, and with a static bandwidth at 4–15 GHz. The results also indicated that directional radiation pattern could be produced at the frequency reconfigurable region and the antenna had a peak gain of 7.56 dBi with an average efficiency of more than 67%. The MTM-based reconfigurable antenna was also tested under the deformed condition and analysed in the vicinity of the breast phantom. This microwave imaging system was used to perform simulation and measurement experiments on a custom-fabricated realistic breast phantom with heterogeneous tissue composition with image reconstruction using delay-and-sum (DAS) and delay-multiply-and-sum (DMAS) algorithms. Given that the MWI system was capable of detecting a cancer as small as 10 mm in the breast phan�tom, we propose that this technique may be used clinically for the detection of breast cancer

ENG and NZRI Characteristics of Decagonal- Shaped Metamaterial for Wearable Applications

A decagonal-shaped split ring resonator metamaterial based on a wearable or textile-based material is presented in this work. Analysis and comparison of various structure sizes are compared considering a compact 6×6 mm2 metamaterial unit cell, in particular, where robust transmission-reflection (RTR) and Nicolson-Ross-Weir (NRW) methods have been performed to extract the effective metamaterial parameters. An investigation based on the RTR method indicated an average bandwidth of 1.39 GHz with a near-zero refractive index (NZRI) and a 2.35 GHz bandwidth when considering epsilon negative (ENG) characteristics. On the other hand, for the NRW method, approximately 0.95 GHz of NZRI bandwidth and 2.46 GHz of ENG bandwidth have been observed, respectively. These results are also within the ultra-wideband (UWB) frequency range, suggesting that the proposed unit cell structure is suitable for textile UWB antennas, biomedical sensors, related wearable systems, and other wireless body area network communication systems

Radiation pattern reconfigurable fm antenna

In this work, a radiation pattern reconfigurable antenna design using compact printed spiral monopoles that operates at 102 MHz is reported. The proposed antenna changes its radiation behaviour that responds towards a desired direction with the use of RF switches. The antenna is printed on a 76.6mm × 50mm PCB layer providing more than 20MHz bandwidth at -10 dB threshold and is easily fabricated with low manufacturing cost. The antenna was also simulated on 500mm × 500mm ground plane that represents the roof top of a vehicl

A Flexible and Compact Metamaterial UHF RFID Tag for Remote Sensing in Human Health

This paper presents a miniaturized UHF RFID tag antenna with increased gain using meander line techniques and metamaterial (MTM). The designed tag operates in the UHF RFID frequency band ranging from 860 to 960 MHz. It comprises of meandered lines with two hexagonal split ring resonators (H-SRRs) MTM cells. It is designed on a photo paper as its substrate which is 0.27 mm thick, with a dielectric constant of 3.2 and loss tangent of 0.05. Next, an RFID tag (NXP SL381213 UCODE G2iL chip) with an impedance of 23-j224 Ω is integrated with the proposed antenna to assess its performance in terms of reflection coefficient, antenna gain and maximum reading range. The overall size of the tag is 92 mm x26 mm

Design And Analysis Of Rain Fading Mitigation Techniques For Fixed Broadband Wireless Access System

The aim of this research is to propose advanced technical and operational techniques to cope with the time variant responses of LMDS wireless communication channels which are largely affected by rain fading. In an LMDS network, due to the random characteristics of rain, a customer station (CS) could sometimes receive signals from a distant interferer, but not from a close by default base station (BTS). Cell-site diversity (CSD) can take advantage of such scenarios and acts as an effective rain fading mitigation scheme. However, detailed analysis of the CS antenna, switching algorithm and access plan when employing CSD has not been carried out. This work proposes some useful components that could be implemented within a CSD scheme to achieve reliable performance

Reconfigurable four-parasitic-elements patch antenna for high-gain beam switching application

A reconfigurable beamforming of a four-parasitic-elements patch antenna (FPPA) for WiMAX application is presented. The proposed FPPA is successfully capable to steer the radiation pattern in azimuth planes (0\circ, 45\circ, 135\circ, 225\circ, and 315 \circ angles) and in elevation plane (0\circ, 13 \circ, 15\circ, 10\circ, and 12 \circ). This is realized in the unique form of four parasitic elements encircling the center main radiator. The activation of the parasitic required a shorting pin to the ground that indicates on state condition, and vice versa. It is discovered in CST simulation software that the specified location of the pins are really significant to ensure the parasitic performs either as a reflector or director. Moreover, each of the shorting pins is linked to the RF p-i-n diode BAR5002v switch. Also, the FPPA is fabricated on a 130-mm square Taconic substrate. The proposed antenna design has a maximum gain of 8.2 dBi at all desired angles with a half-power beamwidth of 58\circ

Location tracking system using wearable on-body GPS antenna

An on-body location tracking system is developed and integrated with a wearable GPS antenna. Such system is beneficial in human location tracking of patients and elderly within a radius of 1 km. The system consists of a wearable antenna, a GPS module, a low cost microcontroller, two RF modules and a local monitoring system. A user equipped with the GPS antenna, GPS module and a RF transmitter is able send his/her location to the local monitoring system via a RF receiver. The proposed wearable antenna is validated to be safe for human use in terms of specific absorption rate (SAR). This antenna was then incorporated into the complete prototype and tested. Several suggestions for future improvements are also proposed and discussed

Location tracking system using wearable on-body GPS antenna

An on-body location tracking system is developed and integrated with a wearable GPS antenna. Such system is beneficial in human location tracking of patients and elderly within a radius of 1 km. The system consists of a wearable antenna, a GPS module, a low cost microcontroller, two RF modules and a local monitoring system. A user equipped with the GPS antenna, GPS module and a RF transmitter is able send his/her location to the local monitoring system via a RF receiver. The proposed wearable antenna is validated to be safe for human use in terms of specific absorption rate (SAR). This antenna was then incorporated into the complete prototype and tested. Several suggestions for future improvements are also proposed and discussed