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International audience; In this paper, a novel method to improve the readability of chipless tags is presented. When the EM wave falls upon the tag's surface at normal incidence or with a known incidence, the proposed approach permits to obtain a higher signal-to-noise ratio (SNR) of resonators whose orientation with respect to the normal to the plane in which the tag is positioned is unknown and thus, to increase the reading distance of the tag. It introduces a technique based on the detection of this tag orientation in relation to the antennas; a projection of the signals will allow to correct this misalignment in order to always be able to decode the tag identifier on a signal that corresponds to an ideal alignment between the tag and the antennas. With this principle, it is also possible to separate the resonance mode of the resonator that is connected to the identifier from other parasitic resonance modes that may appear due to a possible misalignment between the tag and the antenna. This principle is applied to loop resonators commonly used in chipless RFID which can present strong parasitic modes of resonance. Also, this method makes the reading orientation invariant, allowing to read the resonator whatever its orientation with respect to the normal to the plane in which the tag is positioned. Likewise, the proposed method can be also used to sense this resonator orientation. This method requires a dual-polarization antenna and a 2-ports vector network analyzer (VNA). Results are validated in simulation and with real-environment measurements for a single resonator as well as for multiple resonators, as it is classically used in the chipless RFID technology. Measurements in a harsh environment, as well as comparisons with classical techniques such as time gating, are presented. A study on the improvment of the read range is achieved to highligth the potential of the proposed technique. A reading distance of more than 80cm was thus obtained, which represents 20cm more than with the classic use of a post-processor based on time gatting. Finally, the principle of the measurement is generalized by applying it to a tag with a ground plane and considering that the antenna is not necessarily placed in normal incidence with respect to the plane of the tag.

International audience; This paper presents an analytical model of the radiation pattern of a loop resonator which is frequently used as chipless RFID tags. The radiation pattern of this resonator can be used in practice as a sensor to determine the orientation between the tag and the antenna. Contrary to already implemented chipless RFID angle sensors, the one introduced here allows to extract rotation of the tag or the antenna position in 3D using a novel approach based on the resonator radiation pattern. An analytical model is developed to measure the tag orientation determining both the inclination and azimuthal angle of the tag in spherical coordinates system for both mono-static and bi-static antenna configurations. Uncertainties are studied with Monte-Carlo simulations. Simulations and measurements are performed to validate the orientation extraction and evaluate the performance of the proposed solution. We show that the accuracy of this totally passive and wireless sensor is always below 5°in the measurable range with a maximum error lower than 3°for the mono-static case.

International audience; In this paper, a method to characterize complex permittivity of dielectric is presented. The back-scattered signal from a resonant scatterer placed in contact with the dielectric is used to estimate the dielectric properties. The proposed method was tested in simulation and validated in practice using different dielectric samples and different dielectric thicknesses. This method is wireless, non-destructive, with no restriction on the sample thickness and is done using a VNA and an antenna. Discussions on the geometry of the resonator as well as the calibration step is proposed in order to improve the sensing capability of the approach. Monte-Carlo simulation has been performed to define a confidence interval for the values extracted with the proposed approach in the range 1 to 3.5 for permittivity and 0 to 0.2 for tan δ with a SNR of 20dB. For example, a permittivity εr = 3.54 ± 0.06 and tan δ = 0.0024 ± 0.003 has been measured for Rogers RO4003C and εr = 2.31 ± 0.05 and tan δ = 0.004 ± 0.002 for Duroid RT5880 with different thicknesses. It is also shown in simulation that the approach is compatible with materials having loss tangents up to 0.5, and real permittivity up to 10.

The purpose of this work is to design an energy scavenging system. The system scavenges ambient energy from indoor Wi-Fi routers. It makes use of low cost, environment-friendly and widely available corrugated cardboard substrate. The circuit design is realized on metallic layers made of low-cost copper tape. A Villard rectifier is used to convert the RF energy into dc. The measured scavenged power of the system at the power density of 10 μW cm−2 is −15.76 dBm (26.5 μW). The measured conversion efficiency is 58.6%. The presented design has the lowest cost among other similar works.

This article introduces a description of the slow wave effect based on the analysis of spatial field separation. Considering an ideal parallel-plate framework, approximate analytical expressions are derived for the slow wave factor (SWF), as well as dielectric attenuation. In particular, it is shown that the SWF can be related to the spatial distribution of both electric and magnetic fields. It is also demonstrated that the dielectric attenuation increases by the same factor as the velocity reduces. The derived principles are applied to a study case consisting of a parallel-plate waveguide partially filled with vertically grown metallic nanowires.

In this paper, a method to increase the coding capacity of chipless RFID tags is proposed. This approach is based on the radiation pattern diversity of different resonators topology or different modes of resonance on the same resonator topology. By using two antennas and therefore two mono-static measurements, with these tags, it is possible to double the coding capacity without increasing the frequency band of operation. In the present manuscript, conventional chipless RFID loop resonators are considered. Two modes of resonance will be exhibited for this resonator and used to encode data. The novelty is the usage of the same frequency slot to encode multiple bits without interfering together.

International audience; In this paper, a temperature and humidity chipless RFID sensor is presented. A conventional chipless RFID interrogation process is used to extract the tag identification as well as the two physical parameters. A model describing the evolution of the resonance frequency of a scatterer as a function of temperature and humidity is introduced. It allows the two quantities to be extracted independently of each other while each of them impacts the resonance frequency. On average, an error lower than 0.7 • C is obtained on the temperature and less than 1.3% on the humidity.

This paper presents Wilkinson power divider (WPD) designs using slow-wave microstrip lines realized in multilayer printed-circuit-board technology. The main objective of this work is to reduce the size of the WPD using simple technique while maintaining similar electrical performance as a conventional WPD realized using conventional microstrip lines. Two Wilkinson power dividers (1:2 and 1:4) are designed and measured. The proposed dividers operate at 2.45 GHz. As compared to WPD realized using conventional microstrip lines, the proposed 1:2 WPD exhibits a size reduction of 44%.

Thermal modeling of different transmission lines (TLs) based on resonant scatterers is presented. The coplanar strip (CPS) and microstrip (MS) TLs are used to model resonators and to introduce the thermal dependence. A reflectometry approach is employed to validate the model by detecting the scatterers’ resonance frequency and comparing it with analytical expressions. The observable shift in the resonance frequency of the scatterers with temperature variations is due to the thermal expansion of metals and temperature dependence of the substrate permittivity. Since all the measurements are done remotely with no direct line of sight, it is shown how such a reflectometry approach can be used for remote temperature sensing using a passive label composed of resonators. Unlike previous works in this domain where the thermal dependence is considered empirically, the introduced model is used to take into account all thermal effects affecting the resonant scatterers allowing to link rigorously the variations of the measured resonance frequency with the temperature without any lookup table. Temperature sensing using very simple TLs based on resonant scatterers was demonstrated in a real environment. A temperature error of less than 3 °C is obtained. Once the temperature has been determined, it is possible to go back to the TL parameters, such as the effective permittivity and the physical length.

In this paper we demonstrate the transformation of optical barcode into UHF RFID tag, which makes the barcode readable by both an RFID reader and an optical reader. The designed structure is fully realized by 3D Printing Technology including both dielectric and conductive components. The tag is provided with a -15 dBm sensitivity RFID chip (Impinj Monza 3) and can be scanned through both a barcode reader and a canonical UHF RFID reader. An RFID read range of 2m is demonstrated which represents an appreciable distance considering the chip sensitivity and the prototyping technique.

International audience; In this paper, a novel method to characterize the thermal dilatation of metals using a contactless measurement of the frequency-dependant reflection coefficient of a resonator is introduced. This wireless technique allows extracting the thermal expansion coefficient of the material without the need of any calibration. Two antennas, a VNA and a scatterer fabricated with the under-test material are required. All the measurements have been achieved using a climatic chamber with absorbers to control the scatterer's temperature. Measured values for thermal expansion coefficients are in good agreement with the values provided by the manufacturer which is confirmed by a sensibility study.

The industrial sector of cheese production with particular quality protection occupies an important position in the industrial context of the European Union. Compared to conventional casein labels, UHF RFID tags can be read at greater distances and can store more information about the product which represents a more reliable solution for traceability. This paper discusses the main challenges of designing UHF RFID tags for the identification of dairy products such as cheese wheels in an industrial environment. Two different realization techniques are presented in this paper, and the performances of the realized prototypes were measured and compared using a professional RFID measurement system and a commercial handheld RFID reader in a real industrial environment.

This letter demonstrates the possibility of combining advantages of barcode and radio-frequency identification (RFID) technologies on the same smart label. In this letter, several UHF RFID tag designs based on barcodes of different standards and sizes are realized and measured using a professional RFID measurement system. Measurements of all realized prototypes are in good agreement with simulations. Interesting results are obtained with a maximum RFID read range reaching around 12 m while keeping the prototypes readability as a standard barcode. Another tag configuration which avoids soldering the IC to the structure and based on the coupling of a near-field RFID tag to the barcode is also presented, showing a read range of more than 7 m.

This work discusses the possibility of using printed organic photovoltaic cells in order to increase the performance of UHF RFID sensor tags. As a proof of concept, an organic photovoltaic (OPV) cell was used to power the chip SL900A that incorporates a sensor front-end interface capable of measuring voltages, currents, resistances, and capacitances. Several read range measurements were realized using other types of power sources and compared to OPV. Results based on the OPV cell showed a significant enhancement in the tag read range (up to 80%) under low light conditions which opens the door for several IoT applications.

This paper discusses the design of an RFID tag for detecting the maturation level of Swiss-type cheese during its ripening process. Several parameters such as carbon dioxide concentration, wheel size, and pressure inside cheese packaging were studied in order to determine the correlation between their variations and the level of cheese maturation. Two configurations of RFID sensor tags were designed and measured. The first sensor tag configuration was based on a stretch sensor in order to detect the increase of the cheese wheel diameter when it starts to swell due to maturation. The second RFID tag design was based on a low power pressure sensor in order to monitor the pressure variation inside the packaging of cheese during the ripening process. Results obtained from both configurations showed a significant variation of the sensors values during the ripening process.

This letter presents the design, simulation, and measurement results of a 3-dB coupler in slow wave (SW) substrate integrated waveguide technology at 11 GHz. It shows the possibility of reducing by 70% of the surface area without significant increase in insertion loss. The topology relies on a uniform distribution of blind via-holes, creating a distributed SW effect. It is therefore applicable to already existing coupling structures, in this case, the short-slot coupler. An equivalent homogeneous substrate defined by an increased permittivity is used to simplify the optimization of the structure. Finally, a good agreement is obtained between simulation and measurement.

The integration of rectangular waveguides inside a nanoporous alumina membrane is proposed in this letter. The horizontal copper plates are realized by a photolithography process while the vertical connections are made of copper nanowires selectively grown inside the nanopores. The lateral wall position can, therefore, be freely adjusted. Waveguides in the $V$ -band (50–75 GHz) and the $W$ -band (75–110 GHz) were manufactured in a 50- $\mu \text{m}$ -thick membrane. For the measurement purpose, wideband transitions from a grounded coplanar waveguide to the waveguide were designed. The measured performance validates the propagation of guided waves with an attenuation constant of about 0.5–0.8 dB/mm in the operating bands, opening the way for the design of functionalized millimeter-wave alumina interposers.

A simple solution to efficient pressure measurement in sports balls using a force sensitive resistance sensor connected to an ultra high frequencies (UHF) radio frequency identification (RFID) tag is presented. The proposed solution has the advantage of increasing the pressure range measurement without changing the configuration of the employed RFID chip. It also offers a small and compact sensor structure due to miniaturised antenna design. The designed antenna is placed between the ball inner and outer layers. Prototypes were fabricated on a flexible substrate to make their integration easy into a sport ball. This smart tag concept was fully validated through measurements on different types of sports balls, and the results successfully compared to data from electronic ball pressure gauge.

This paper presents a miniaturized 3-dB branch-line coupler based on slow-wave microstrip transmission lines. The miniaturized coupler operating at 2.45 GHz is designed and implemented on a double-layer printed circuit board substrate with blind metallic vias embedded in the lower substrate layer providing the slow-wave effect. Based on this concept, a 43% size miniaturization is achieved as compared with a classical microstrip branch-line coupler prototype. The measured S parameters present a return loss of 25.5 dB and an average insertion loss equal to 0.05 dB at the operating frequency.

This paper presents D-band mm-wave SIWs, which are embedded in a high-resistivity silicon interposer. Thanks to the interposer thickness equal to $\pmb{70\ \mu} \mathbf{m}$ , high-performance SIW were obtained, with measured attenuation constant between 0.4 and 0.6 dB/mm from 110 GHz to 170 GHz. These first results pave the way for the realization of high performance passive circuits and antennas embedded in the interposer. Also, by using a fully shielded waveguide highly insensitive to adj acent wave-guiding and radiating structures, this topology provides significant advantages for packaging solutions at mm-wave frequencies. Such a functionalized interposer could offer lower cost, higher electrical performance as compared to standard CMOS technologies.

In this study, we proposed the UHF RFID technology with its passive character and low power consumption as an effective solution for monitoring the operating parameters that improve the plant growth in closed conditions. The designed RFID sensor operates autonomously in a full passive mode and provides measurements of absolute pressure and temperature.

This letter highlights the potential of inkjet-printing on molded interconnect device technology for the realization of ultrawide band (UWB) antennas. Low-cost thermoplastic acrylonitrile butadiene styrene polycarbonate (ABS-PC) substrate is selected for its promising mechanical and thermal properties. First, electrical characterizations of bare ABS-PC are done using resonance cavity method and then the measurements of S-parameters of two 50 $~\Omega $ -CPW transmission lines, allow the extraction of both relative permittivity and RF losses. Inkjet printing of silver nano ink is used to fabricate those CPW lines on the top of a 2-mm-thick ABS-PC. The measurements show a relative substrate permittivity equal to 2.8 with conductive and dielectric losses of 19.5 dB/m and 2.4 dB/m at 2 GHz, respectively. Then, an UWB antenna based on a half circular disc monopole and a rectangular patch with two steps is designed and realized by inkjet on ABS-PC. This printed antenna provides a good impedance matching over the entire bandwidth of 3 GHz–13 GHz. Radiation pattern is omnidirectionnal in both E and H planes until 5 GHz and is deformed at higher frequencies due to the higher order modes.

In this paper, a novel passive UHF RFID sensor configuration is presented. Configurations based on strain gauges are tested. The first configuration uses a flexible substrate to be suitable to measure the bending of a given surface and the second one uses a specific designed structure for measuring absolute force in a limited range. An energy harvesting block that can collect the RF power received from UHF RFID Reader is integrated in order to cover the extra energy supply demand. Realized measurements show a high level of accuracy and reliability of fabricated prototypes.

This article discusses the possibility of making unconventional antenna designs for RFID tags based on artistic figures and symbols. Some classical techniques of impedance matching are used in order to match these structures to commercial RFID chips without modifying a lot the shape of the structure. These tags were simulated on HFSS and their read ranges were measured and compared to a conventional antenna design.

In this paper, an integrated solution based on passive UHF RFID tag sensor is proposed to measure the pressure on different types of sports balls. A comparison of two commercial piezzoresistive sensors based on different technologies is performed for this type of pressure measurement application. Several external sensor interface chip configurations (SFE) have been tested and adapted to the resistance variation range that presents each type of sensor. In both function modes: passive or semi-passive, a smart RFID tag concept is fully validated through measurements on different types of sport balls and the results are compared with data from Electronic Ball Pressure Gauge CJ-01 model.

This paper presents a slow-wave microstrip transmission lines based on a double-layer PCB substrate. The slow wave effect is obtained by inserting metallic via rows within the lower substrate layer. Based on this concept, miniaturized high rejection 5'h order low pass stepped impedance filters with a cut-off frequency of 2.45 GHz are designed, fabricated and measured. Measurement results are in good agreement with simulations. Thanks to the slow-wave transmission lines, the size of the realized filters is reduced by 54% as compared to a classical filter prototype.

This paper presents a non-destructive dielectric characterization method for heterogeneous dielectric samples such as food products. The principle is based on the measurement of the reflection coefficient of a center-fed dipole antenna in a good contact with the sample surface. The sample's dielectric constant is directly related to the dipole resonance frequency. Dielectric constant measurements obtained with the dipole antenna are in good agreement with the ones obtained by electromagnetic simulation software (HFSS) and a commercially available coaxial-line probe.

National audience

International audience;  Abstract-This paper presents a chipless RFID sensor tag having both identification and sensing capabilities. It is based on one resonant scatterer operating as a signal processing antenna in the 3 to 7.5 GHz band. The scatterer is used to monitor a physical parameter variation, as well as to identify the remote sensor. To make a resonator sensitive to the humidity, silicon nanowires are deposited on the tag surface using a simple process. The tag needs only one conductive layer so that it can be directly printed on the products to sense and to identify. Measurements done using a bistatic radar configuration in the frequency domain validate this concept. To demonstrate the reliability of such an application, two chipless RFID sensors placed in various environments are simultaneously detected using an anti-collision technique based on spectral separation.

This paper presents a passive proximity sensor using UHF radio-frequency identification (RFID) technology. The sensing operation allows detecting and counting goods or persons with no RFID tags attached. The system comprises a customized double-antenna sensor tag and a commercial reader. The design is performed at two layers. In the physical layer, a distribution network prioritizes power towards one antenna to detect presence, while allows the other antenna communicating with the reader. In the communication layer, the RFID chip (EM4325) is programmed to set an alarm when triggered by an RF event, and hence changing the tag identifier. Design directives are given and experimental sensing tests consisting of an access gate demonstrates the proposal.

Nowadays, several RFID systems are commercially available for numerous applications such as control assess, transportation, supply chain, etc. However, RFID tags and sensors association could provide a lot of new solutions in order to develop notably green projects such as more efficient energy production chain, best control waste, recycling, and other environmental challenges. Furthermore, the development of these novel solutions requires resolving several technical challenges. This paper focuses on the actual and future roles of RFID as technology contributing to green projects.

Shielded coplanar waveguides are promising candidates for the development of high quality factor transmission lines in millimeter-wave frequency bands. In this article, state-of-the-art experimental results carried out on a CMOS 0.35 μm low-cost technology are presented. This letter especially deals with the benchmark of slow-wave transmission lines in focusing on the impact of technology dispersion on the measurement results. Eight dies have been measured, each from a different wafer, showing a robust design versus the technology. These results open new possibilities for the development of miniaturized low-loss compact passive devices. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2786–2789, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25598

Slow wave coplanar transmission lines (S-CPW), based on conventional coplanar CPW transmission lines with a floating patterned ground plane, consisting in floatting strips below the line, are good candidates for the integration of distributed RF circuits for front-end modules. They offer high quality factors when compared to conventional coplanar transmission lines. In this paper, guidelines are carried out for the design of such transmission lines. Simulations are first compared to already published measurements thus validating the simulation method used throughout the paper. Next, considering a standard 0.35 µm CMOS process, a design guideline is drawn in order to determine the characteristic impedance, the phase velocity and the dielectric effective constant of the S-CPW transmission lines, along with the attenuation loss and the quality factor. The effects of the floating strips duty cycle, the floating strip width and the ground plane width are studied.

National audience

National audience

This paper describes a miniaturized substrate integrated waveguide (SIW) filter by considering slow-wave substrate integrated waveguides. Compared to conventional SIW, the proposed topology includes internal blind metalized via-holes connected to the bottom metalized layer. These via-holes tend to confine the electric field in the upper part, while the magnetic field remains present in the whole substrate. Thus, a slow-wave effect is obtained by the physical separation of electric and magnetic fields. Using this novel topology, a 5th-order cavity filter centered at 11 GHz exhibiting a bandwidth of 900 MHz was designed, realized and measured. The filter surface area is more than three times smaller compared to classical SIW approaches. Measurements are in good agreement with simulations, validating the potential of the SW-SIW topology for RF and millimeter wave applications.

International audience; In this paper, microstrip transmission lines and antennas realized on Molded Interconnect Devices (MIDs) are presented. Measurements of two transmission lines realized by LDS on LCP vectra E820i substrate and inkjet printing on ABS PC substrates allowed the extraction of LCP vectra E820i and ABS PC permittivities. Measurement results show that lower losses are obtained with the LDS fabrication technique, validating thus the potential of MIDs for RF applications. The measurement results of the two microstrip patch antennas realized by Laser Direct structuring (LDS) on LCP vectra E820i substrate and inkjet printing on ABS PC substrate are made in good agreement with simulations.

International audience; An original design of 3D-MID antenna for passive UHF RFID tags is presented in this paper. For the first time the integration of RFID tag into the MID technology is considered. The novel tag based on a meander antenna and placed on the external face of a thermoplastic cylinder (LCP Vectra E820i) is compatible with Laser Direct Structuring (LDS) process. Both planar and 3D designs on MID substrate are discussed. In particular the influence of the 3D implementation on the RFID Tag performance is studied. Simulation results confirm the potential of this 3D design.

International audience; The continual trend of miniaturization and increasing complexity in the field of Radio Frequency (RF) devices poses a challenge for today's manufacturing technologies. The possibility of miniaturization of RF components with Molded Interconnect Devices (MIDs) is very attractive. However, electromagnetic properties of MID substrates based on polymer materials and behavior of RF basic components designed on MID substrates are not well known in the literature. In this paper, some MID substrates complex permittivity measurements and dielectric losses measurements are presented and exploited to design RF basic components. LCP Vectra E820i is used for the realization of transmission lines and a low pass filter in Coplanar Waveguide (CPW) technology by Laser Direct Structuring (LDS). Measurements, which are in good agreement with simulations, make MIDs good candidates for RF applications.

International audience; This paper presents a chipless RFID tag having both identification and sensing capability. It is based on 5 resonant scatterers that behave as signal processing antennas in the band from 2.5 to 7.5 GHz. Only one scatterer is used to monitor a physical parameter variation, while the four others allow identifying the remote sensor with 13 bits. To make a resonator sensitive to the temperature or humidity, a material based on Silicon Nanowire is deposited on the tag surface using a very simple process. The tag needs only one conductive layer so that it can be directly printed on product making by the way a unit cost potentially very low. Measurements done using a bi static radar configuration in the frequency domain validate this new concept.

International audience; A Coplanar WaveGuide (CPW) monopole antenna designed to operate at the frequency (fr) of 2.05 GHz and intended to be put over a fabric is tested with respect to substrate deformations. In absence of deformations, the antenna bandwidth is 18.8% and its reflection coefficient is -44 dB. Deformations tested are bending in the H or the E-plane, crumpling and a combined situation. Results show that bending effect will not greatly affect the antenna in realistic situations (i.e. bending radius bigger or equal to 5 cm). Crumpling effect is more important and should be prevented.

The rapid development in wireless identification devices and subsequent applications is at the origin of intensive investigations in order to fulfill various constraints that can exist when implementing applications in practice. Chipless technologies have many advantages. They are fundamentally wireless and powerless devices, and can be all passive components, which potentially means infinite lifetime. However, chipless technology is still in its infancy age, even if it is the most effective for cost reduction. One of the most important features of chipless is coding capacity and ways to imprint it into the device. This chapter will review and discuss various coding techniques. It will address a comparison of the most relevant coding techniques. For sake of clarity some global parameters that can be used as figure of merit will be introduced and applied to compare different practical chipless tags.