An Overview of Near Field UHF RFID

Никитин, П.В.; Rao, K. V.; Lazar, Stefania

doi:10.1109/rfid.2007.346165

Cited by 290 publications

(143 citation statements)

References 70 publications

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“…tag th P G p P τ = ⋅ ⋅ ⋅ (1) where G is the antenna gain of the tag, p is the polarization efficiency, τ is the impedance matching coefficient between the antenna of the tag and its chip, P th is the threshold power. This equation allows to know the minimum power that must be absorbed by the tag to make the chip in the condition to operate.…”

Section: Type Of Tagsmentioning

confidence: 99%

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RFID-Based Smart Shelving Storage Systems

D’Alessandro

Buffi

Nepa

et al. 2012

2012 Asia Pacific Microwave Conference Proceedings

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Section: Type Of Tagsmentioning

confidence: 99%

“…The aim of Passive Radio Frequency Identification (RFID) is to identify objects, animals, people, through radio frequency (RF) transmissions [1]. The main advantage, respect at the well-known barcodes, is to detect object at more distance without direct visibility between transmitter and receiver ( Fig.…”

Section: Introductionmentioning

confidence: 99%

RFID-Based Smart Shelving Storage Systems

D’Alessandro

Buffi

Nepa

et al. 2012

2012 Asia Pacific Microwave Conference Proceedings

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“…Wireless energy transfer methods based on near-field coupling (D<λ/2π), where D is the distance and λ is the wavelength) have widely been studied for biomedical implants, wireless sensors and RFID tags [1][2][3][4]. The general goal in these techniques is to transfer the data and required energy to a small terminal in a wireless manner.…”

Section: Introductionmentioning

confidence: 99%

“…An efficiency of 40% for 2m distance was achieved. However, the magnetic coupling between the coils and therefore the energy transfer efficiency decreases significantly as the coil sizes shrink, due to the almost linear relationship between the area of the transmitting and receiving coils and the mutual coupling between two coils, M, approximated as [9][10][11]: (1) In addition, the resonance quality factor (Q) is proportional to the radius of the coil and the conductor thickness. Therefore, energy transfer efficiency is degraded significantly as the coils become smaller and their wires become thinner.…”

Section: Introductionmentioning

confidence: 99%

Mid-range wireless energy transfer using inductive resonance for wireless sensors

Mazlouman

Mahanfar

Kaminska

2009

2009 IEEE International Conference on Computer Design

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Abstract-Methods are suggested and tested to measure and optimize the wireless energy transfer efficiency for mid-range (10-100cm) inductive coils with relatively low profile using magnetic resonance. These coils can be used to provide energy for wireless sensors and battery-operated devices. It is shown that for every system, a resonance frequency can be identified where the wireless energy transfer efficiency is optimal. Several prototypes are developed and tested as a proof of validity of the proposed technique. It is also shown that by tuning to the optimum resonant frequency and designing proper matching circuitry, an efficiency of about 25% for moderate profiles can be achieved. I. INTRODUCTIONWireless energy transfer methods based on near-field coupling (D<λ/2π), where D is the distance and λ is the wavelength) have widely been studied for biomedical implants, wireless sensors and RFID tags [1][2][3][4]. The general goal in these techniques is to transfer the data and required energy to a small terminal in a wireless manner. The major advantage of magnetic energy transfer methods is low sensitivity to its surroundings, which is mainly composed of magnetically neutral material, thus not interacting with the coupled magnetic field. The other, rather more important advantage, compared to radiated energy transfer, is that the magnetic fields are of less health concern. Different tissues in human body are all electrically lossy material and dissipate the energy in form of heat when exposed to electric field, but their permeability is unity; therefore the human body does not interact with magnetic fields.Optimized inductive links have been reported to transfer energy with efficiencies of up to 90% for very short distances (less than 1-3cm) [5]. However, the efficiency of these inductive links drops significantly for longer ranges (decays as 1/r3 [6]). In [7][8], the transmitting and receiving circuitry were forced to tune to a resonant frequency. This approach has been proven to be useful for energy transfer in very short ranges.A wireless non-radiative mid-range (10-100cm) energy transfer method based on inductive resonance was suggested in [9][10][11][12]. Based on this method, the transmitting and receiving circuitry are designed such that they are tuned to a resonant frequency with high quality factors (Q); therefore the distance between the energy emitter and receiver (D) can be increased to multiples of the device characteristic size (L dev ), i.e. D ~ α*L dev (1≤α≤5) , with an efficiency much higher than that obtained by conventional inductive nonresonant coupling methods [8][9][10]. This method is used to empower coils of radii of 30cm with wire cross section of 3mm. An efficiency of 40% for 2m distance was achieved. However, the magnetic coupling between the coils and therefore the energy transfer efficiency decreases significantly as the coil sizes shrink, due to the almost linear relationship between the area of the transmitting and receiving coils and the mutual coupling between two coils, M, approx...

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“…The reader antenna is an important unit of RFID systems. Many new RFID antennas are developed for different applications [3][4][5][6][7]. Reader antennas can be classified into two types based on the working scope for different application purposes: near-field antenna and far-field antenna.…”

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confidence: 99%

Near-Field Antenna of RFID System

Xing¹

2017

Radio Frequency Identification

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Radio frequency identification (RFID) technology is a very important part of the Internet of Things. The antenna used in RFID system reader is one of its most important equipment, has become a research hotspot. Compared to far-field applications, RFID antennas typically use high-gain circularly polarized antennas or antenna arrays to increase their read distance. Near-field RFID reader antenna requires strong magnetic field, wide band and low gain characteristics, while the resulting magnetic field should be evenly distributed to avoid leakage read phenomenon. The main contents of this chapter are as follows. The RFID reader near field antenna based on the principle of magnetic field coupling has developed rapidly in recent years. In this paper, a double-layer open-circuit antenna are proposed. The near-field antennas have wideband and strong magnetic field characteristics, and are compact and simple to process. The open-loop antenna of the doublelayer terminal is located at the lower level and the upper layer is the radiation ring. The antenna size is smaller, and the feeder part and the radiation part of the isolation, a good deal to avoid interference between each other. Keywords: RFID, near field, antenna, electrically large Concept of near-field antennaRadio frequency identification (RFID) technologies, which were developed during the World War II, provide wireless identification and tracking capability [1,2]. The reader antenna is an important unit of RFID systems. Many new RFID antennas are developed for different applications [3][4][5][6][7]. Reader antennas can be classified into two types based on the working scope for different application purposes: near-field antenna and far-field antenna. Currently, ultra-high frequency (UHF) near-field RFID technology are fast developed in item-level identifications such as sensitive products tracking, biological products and medical products (blood, medicines, vaccines), biosensing applications and so on [8][9][10][11][12].

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An Overview of Near Field UHF RFID

Cited by 290 publications

References 70 publications

RFID-Based Smart Shelving Storage Systems

RFID-Based Smart Shelving Storage Systems

Mid-range wireless energy transfer using inductive resonance for wireless sensors

Near-Field Antenna of RFID System

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