Stephane Protat

Pebbles Tracking Thanks to RFID LF Multi-Loops Inductively Coupled Reader

The Radio Frequency IDentification (RFID) Low Frequency (LF) serial loops structure is proposed to improve TAGs detection when a TAG coil-antenna rotates by any angle, due to the tagged pebble moving. The detection zones of two types of TAGs (the token and glass TAG) and two types of reader coils, in function of the TAG size, TAG orientation and shape of the reader coils are tested. The effect of the proposed multi-coil inductively coupled is confirmed by measurement using a commercial LF RFID system.

A Multilayered Coil Antenna for Ingestible Capsule: Near-Field Magnetic Induction Link

A compact multilayered stacked ingestible coil antenna is investigated for medical systems. The inductive link, comprising a 5-layer transmitter coil antenna and a 3-turn receiver spiral coil, is modeled through a tissue-simulating liquid modeling the human body. The diameter and the thickness of the transmitter coil are respectively equal to 1 cm and 5 mm, while the dimensions of the receiver coil are equal to 7 × 8 cm2. The variations of the position and the orientation of the capsule antenna are taken into account to evaluate the coupling response between the two magnetically coupled coils. We found that the inductive link presents an attractive option for improving the lifetime of ingestible capsules.

Link Budget of Magnetic Antennas for Ingestible Capsule at 40 MHz

Magnetic antennas are suitable in short range medical in-body applications because they are less perturbed in the presence of the human tissues comparing to electrical antennas. After a preliminary study on magnetic antennas designed separately at 40 MHz with a matching system, a link budget between a spiral coil ingestible capsule transmitter antenna and a square coil onbody receiver antenna has been established in the presence of the human body. The efficiency (ratio of received power to transmitted power) of the magnetic induction link through a homogeneous human body (muscle) is equal to 0.6 % when the TX (transmitter) capsule is in front of the RX (receiver) antenna. If the transmission channel is a three-layered human body (muscle / fat / skin) the performances of the inductive link can be enhanced and the efficiency reaches 0.8 %. These performances can be improved (up to 1 %) when the dimensions of the receiver antenna increase. Consequently, the power consumption can be reduced and hence the battery life of the wireless capsule increases. Additionally, when the TX antenna is located randomly at an arbitrary orientation and position, the efficiency of the magnetic induction link can be improved by orienting the RX antenna parallel and perpendicularly to the human body surface.

Detecting range and coupling coefficient tradeoff with a multiple loops reader antenna for small size RFID LF tags

This paper summarizes some tests with Low Frequency (LF, 125 kHz) RFID tags of two types: Card and Token. These tests were done in order to evaluate the feasibility of an identification/traceability of tags which size is constrained and supposed to be detected inside a delimited volume of 40×40×10 cm3. As the size of the antenna tag is supposed to be very small, we improve the detection range and volume of definition by designing different reader antennas. Reader antennas presented are of two types whether they are based on single (SL) or multiple loops (ML). Detection range was evaluated for planar antennas (3 SL and one ML). Volume of definition for the detection was estimated by designing two-level prototypes of ML antennas. Results are discussed about the optimization possibility of detection range and volume thanks to ML.

Magnetic loop antenna for wireless capsule endoscopy inside the human body operating at 315 MHz: Near field behavior

In ingestible systems, the antenna suffers from deterioration of performances due to surrounding dissipative tissues. A small circular magnetic loop antenna, whose diameter is equal to 1 cm and thickness is equal to 0.5 mm operating at the frequency of 315 MHz in the ISM band, is proposed to limit this degradation. The electric properties of the human body, having a high dielectric constant and low impedance, are considered to design and simulate the loop antenna. We found that the magnetic field is less attenuated than the electric field in the human body that improves the signal level received by near field magnetic coupling.

Performance Analysis of UHF RFID Tags Dedicated to Power Supply Cords

This communication describes the embedding of UHF RFID tags dedicated to power supply cords. A general purpose commercial RFID module is coupled to microstrip dipoles to realize tags, which are wrapped and taped around the cords. The tag dimensions are optimized for a maximum power transmission to the chip and a maximum reading distance in the presence of the cord. Experimental read ranges of the order of 5 m are obtained, whereas commercial tag outperforming the optimized tag in free-space only performs well at 2 m on power cords.

Distributed Diameter sub-Coil Twisted Loop Antenna in non-radiative WPT

This letter focuses on the high-frequency wireless power transfer by electromagnetic induction and its dependence on the lateral misalignment and tilt of the small receiving coil relative to the transmitting coil. We combine two structures, the twisted loop antenna (TLA) and subcoils of a distributed diameter coil (DDC) for transmitting designs. Our system is then referred to as TLA-DDC. The radius of the subcoils is parametrically varied for different distances between the coils and performed in two positions for each distance (coaxial position when the receiving coil is parallel to the plane of the transmitting coil, and center position for the perpendicular orientation of both coils). Then, using different radii for the transmitting DDC TLA when the receiving coil is moved onto its surface allows us to obtain a greater value of efficiency at different positions: up to 2.4 times for the peak value and 1.5 for the average value for receiving coil in parallel plane. The efficiency of the magnetic coupling is determined by means of power efficiency with a comparison between the DDC TLA antennas and a standard coil antenna corresponding to the same inductance value.

UHF RFID Tags for electrical cables

Tagging power cords is not only useful for tracking insulated or hidden electrical cables. Implementing sensory functionalities to the UHF RFID tag in addition to its unique ID is of great interest in the wireless sensing of house electrical appliance activities. Tags dedicated to electrical cables for read distances of 10–12 feet are commercially available (Sentry cable RFID Tag, Vizinex company). The core of the tag is a fiber-reinforced composite material and the mounting uses zip ties or metal banding which makes these tags bulky. Therefore, this type of tags can only be fixed on cables once the electrical installation is complete.

Considerations on the use of commercial loop modules in the excitation of UHF RFID antennas

The purpose of this paper is to clarify the principles, advantages and disadvantages of commercial RFID modules combining a loop and a RFID IC for the excitation of dipole-like antennas. Using a circuit modeling of the tag topology, the influence of the main parameters (dipole radiation resistance and Q factor, module position along the dipole, mutual coupling between the loop module and the dipole) are stressed. A special attention is brought to the determination of the optimal coupling for a given dipole.

Coplanar-Pgl Transitions on High Resistivity Silicon Substrate in the 57-64 GHz Band and Influence of the Probe Station on the Performances

We present Coplanar-Planar Goubau Line (PGL) transitions designed on high-resistivity Silicon to characterize a PGL using microwave probing. These transitions are optimized in the 57{ 64GHz frequency band to present excellent electrical performances despite the fleld disturbance of the measurement setup. As the transitions are positioned on a probe station chuck, a glass substrate is added between the transition under test and the metallic chuck to minimize the disturbance. 3-D full- wave electromagnetic fleld simulations performed on a commercial software and on-wafer measurements show almost comparable results in term of scattering matrix parameters. Low losses are attained with a measured average transmission parameter of 2.5dB at 60GHz for a length of 8mm of a back-to-back structure with the transitions at the extremities. The measured average insertion loss and return loss per transition are better than 1.36dB and 11dB, respectively, with a bandwidth greater than 7% at 60GHz for a length of 1mm (about a half of the wavelength at 60GHz).