The Kynix Blog

This article will introduce to you how RFID sensors are applied to detecting food quality and monitoring food safety.   Catalog I. Brief Introduction II. General Principles of Design and Operation of RFID Food Sensors III. Example of Applications FAQ I. Brief Introduction   Radio frequency identification (RFID) sensors are finding their diverse applications when an unobtrusive sensor form factor, battery-free design, and minimal sensor cost are the top three requirements for a new sensor. Examples of diverse applications include pharmaceutical, warehousing, agricultural, industrial, food safety, and security.    Benefits of RFID sensors for food quality and safety, as compared to tethered sensors, include the non-obtrusive nature of their installations, higher nodal densities, and lower installation costs without the need for extensive wiring.   In addition, a significant advantage of RFID and other electronic sensors over optical sensors is in the ability to perform measurements through non-transparent packaging.   There are several developed battery-free wireless sensing technologies based on magnetoelastic,16 thickness-shear modes, surface acoustic wave, magnetic acoustic resonance, and resonant LCR (inductor-capacitor-resistor) transducers. Several approaches for battery-free RFID sensing have been explored, e.g. based on chipless RFID sensors.   We recently developed a methodology to implement passive RFID tags for physical, chemical, and biological sensing. In our RFID sensing approach, the resonance impedance spectrum of the sensor antenna is measured and further correlated with the chemical, biological, or physical properties of the environment. This correlation is performed using the multivariable response of the RFID sensor computed from the measured impedance spectrum.   The complementary driving forces in successful sensor development are innovative ideas and the market size for new sensors. The market size is often but not always is supported by the regulatory requirements. If both driving forces are strong, the sensor development moves from its initial proof-of-concept technology readiness level to the commercialization of the sensor technology.   The sizes of markets for food safety testing products ($0.25 B) and pathogen detecting sensors ($0.5 B) and provide exciting opportunities for the development of new sensing technologies for food quality and safety.   Intelligent labeling of food products to indicate and report their freshness and other conditions is one of the important possible applications of the developed RFID sensors.   Unlike other food freshness monitoring approaches that require a thin-film battery for operation of an RFID sensor and fabrication of custom-made sensors, our developed passive RFID sensing approach combines advantages of both battery-free and cost-effective sensor design and offers response selectivity that is impossible to achieve with other individual sensors.   In this review, we summarize the result of the development of RFID sensors for food quality and safety. In these sensors, the electric field generated in the RFID sensor antenna extends out from the plane of the RFID sensor and is affected by the ambient environment providing the opportunity for sensing.   This environment may be in the form of a food sample within the electric field of the sensing region or a sensing film deposited onto the sensor antenna. Examples of applications include monitoring of freshness of milk, the freshness of fish, and bacterial growth.   II. General Principles of Design and Operation of RFID Food Sensors     (Figure 1) Operation principle of developed passive RFID sensors. (A) Sensor equivalent circuit described by the inductance LA, capacitance CA, and resistance RA of the sensing antenna coil, capacitance CS and resistance RS of the sensing region, and capacitance ...   In order to assess the broad applicability of the developed sensors for food safety applications, it is critical to understand the general principles of their design and operation (see Figure 1).   The equivalent circuit of the developed sensors forms an inductor-capacitor-resistor (LCR) circuit and is described by the inductance LA, capacitance CA, and resistance RA of the sensing antenna coil, capacitance CS and resistance RS of the sensing region, and capacitance CC and resistance RC of the integrated circuit (IC) chip (see Figure 1A).   Reading and writing of digital information into the RFID sensor and measurement of the impedance of the RFID sensor antenna are performed via mutual inductance coupling between the RFID sensor antenna and the pickup coil of a digital/analog sensor reader.   Impedance spectra Ž(f) of the sensor are measured using a laboratory or a portable network analyzer component and digital data from an IC chip is measured with a digital RFID reader component29 of our custom sensor reader.   Digital data include sensor calibrations, food manufacturing data, end-user data, etc. The network analyzers are used to scan the frequencies over the range of interest (typically centered at 13 MHz with a scan range of ~10 MHz).   The electric field generated in the RFID sensor antenna extends out from the plane of the RFID sensor (Figure 1B) and is affected by the ambient environment providing the opportunity for sensing. This environment may be in the form of a food sample within the electric field of the sensing region or a sensing film deposited onto the sensor antenna.   In both cases, the impedance of the antenna circuit Ž(f) is modulated through the changes in capacitance CS and resistance RS of the sensing region. This sensing region can be in the form of a full antenna or a complementary region in contact with the antenna.32 Numerous types of sensing materials applicable for food quality sensing were recently analyzed.   To achieve accurate and precise measurements using our sensors, we measure the real Zre(f) and imaginary Zim(f) parts of the impedance spectra Ž(f) and calculate several spectral parameters.   A schematic representation of the real Zre(f) and imaginary Zim(f) parts of the impedance spectrum Ž(f) of the sensor without possible effects from a pickup coil is illustrated in Figure 1C. Several calculated spectral parameters include the frequency position Fp and magnitude Zp of Zre(f) and the resonant F1 and antiresonant F2 frequencies of Zim(f).   Additional parameters can also be calculated (impedance magnitudes Z1 and Z2 at F1 and F2 frequencies, respectively, zero-reactance frequency, quality factor, etc). From the measured parameters, resistance, capacitance, and other parameters of the resonant antenna can be also determined. Figure 2 shows examples of RFID sensors applied in our studies for food quality and safety.       (Figure 2) Examples of employed RFID sensors based on (A) Texas Instruments RFID tag, (B) Avery Dennison RFID tag, (C) TagSys RFID tag.   Uncontrolled temperature fluctuations produce independent effects on the different components of the equivalent circuit. These independent effects are correlated with the spectral features of the resonance impedance spectra and are resolved by the multivariable response of the sensor.   For scenarios when the food is irradiated by ionizing radiation as a food safety measure to destroy bacteria, pathogens, and pests,39,40 conventional RFID IC memory chips do not survive the applied radiation dose that can be up to 30 kGy.   We have developed a technical solution to solve this problem where an IC chip is based on the Ferroelectric Random Access Memory (FRAM) technology and provides reliable gamma-resistant RFID tags and sensors.   The FRAM memory chips have 2000 bytes of user memory (MB89R118A, Fujitsu Microelectronics Ltd, Japan)42 and are made using a standard RF signal modulation circuitry fabricated using a 0.35-μm complementary metal-oxide-semiconductor (CMOS) process and a non-volatile FRAM memory.43 A photo of this IC chip is shown in Figure 3A while one of our RFID sensors with such an IC chip is shown in Figure 3B.   (Figure 3) Photographs of (A) FRAM IC memory chip MB89R118A and (B) Developed RFID sensor for gamma-sterilizable applications. Sensor diameter = 10 mm. III. Example of Applications       · Monitoring of milk freshness     · Monitoring of fish condition     · Direct monitoring of bacteria growth FAQ   1. What is RFID used for? Radio Frequency Identification (RFID) is the wireless non-contact use of radio frequency waves to transfer data. Tagging items with RFID tags allows users to automatically and uniquely identify and track inventory and assets.   2. What is RFID and how it works? RFID is a method of data collection that involves automatically identifying objects through low-power radio waves. Data is sent and received with a system consisting of RFID tags, an antenna, an RFID reader, and a transceiver.   3. What RFID means? Radio Frequency Identification (RFID) refers to a wireless system comprised of two components: tags and readers. The reader is a device that has one or more antennas that emit radio waves and receive signals back from the RFID tag.   4. Is RFID harmful to human? It is a non-ionizing type of radiation, but some researches show that it could have a negative impact on the human body in a long-term period [11, 12]. So, for the safety reasons, manufacturers of the RFID systems have limited the range of the RFID antennas used in their systems.   5. Is RFID tag and FASTag same? FASTag is a device that employs Radio Frequency Identification (RFID) technology for making toll payments directly while the vehicle is in motion. FASTag (RFID Tag) is affixed on the windscreen of the vehicle and enables a customer to make the toll payments directly from the account which is linked to FASTag.   6.What is RFID and its advantages? RFID technology automates data collection and vastly reduces human effort and error. RFID supports tag reading with no line-of-sight or item-by-item scans required. RFID readers can read multiple RFID tags simultaneously, offering increases in efficiency.   7. Why is RFID bad? Some negative effects are that its deadly, if RFID tags combine with static electricity you can die. Another negative effect is that the government is slowly taking away surviving resources and giving ultimatums, such as if you don't get the RFID tracking chip your public assistance will be terminated.   8.What are the disadvantages of RFID? a. Materials like metal & liquid can impact signal. b. Sometimes not as accurate or reliable as barcode scanners. c. Cost – RFID readers can be 10x more expensive than barcode readers. d. Implementation can be difficult & time consuming.   9.How do I charge my RFID FASTag? In order to recharge your FASTag sticker, just hit the Add Money option in your Paytm app. FASTag will automatically reserve some amount from your wallet, which can be used at toll plazas later. Do note that FASTag can be used only after 20 mins of adding money to the Paytm Wallet.   10. Can I use existing RFID for FASTag? If a vehicle already has an RFID tag, it might already be activated. When you buy the vehicle, RFID tag payment was also done. It might also have a minimum balance of INR 100 or 200 as is required by the bank. You can recharge it with your Customer ID or Wallet ID of FASTag.   11. How does RFID work without power? Passive RFID tags have no power of their own and are powered by the radio frequency energy transmitted from RFID readers/antennas. The signal sent by the reader and antenna is used to power on the tag and reflect the energy back to the reader.   12. What are the types of RFID tags? RFID tags can be grouped into three categories based on the range of frequencies they use to communicate data: low frequency (LF), high frequency (HF) and ultra-high frequency (UHF). Generally speaking, the lower the frequency of the RFID system, the shorter the read range and slower the data read rate.   13.How do I know if I have an RFID chip? The best way to check for an implant would be to have an X-ray performed. RFID transponders have metal antennas that would show up in an X-ray. You could also look for a scar on the skin. Because the needle used to inject the transponder under the skin would be quite large, it would leave a small but noticeable scar.   14. Does RFID require power? Active RFID tags possess their own power source – an internal battery that enables them to have extremely long read ranges as well as large memory banks. Typically, active RFID tags are powered by a battery that will last between 3 - 5 years, but when the battery fails, the active tag will need to be replaced.   15. What is the difference between a QR code and RFID? QR codes must always be “read-only”, whereas RFID tags can be “read-write”, depending on the radio frequency that's being used. ... So, not only are RFID tags futuristic and have more uses than QR tags, they also have many more applications. The read range is far superior for an RFID tag.   Ref. KY45-R300-F35-M14-C KY78-2867704

Yes, current Wi-Fi-based smart home technology can turn on the lights with your smartphone or voice. But do you call that home automation, really? Isn’t it just a slightly more convenient light switch? How about this? When you unlock your front door, the lights in the foyer come on, the motion sensors on your alarm system turn off, the thermostat starts the air conditioning, and your entertainment system begins playing your favorite music—all before you put your keys down!Now that’s home automation, right? What about a more serious, or potentially life-and-death scenario, where hospital staff could track patients, staff members, and equipment from any console, PC, or tablet on the premises? While the best Wi-Fi systems allow us to take baby steps into building automation, wireless security, asset tracking, and more, a new technology called Bluetooth Mesh — an update to the standard Bluetooth wireless solution that most of us know — promises a better, more efficient, and much less expensive solution. “As people’s expectations for networks go up, they demand networks capable of handling hundreds (or thousands) of IP addresses, offering Wi-Fi-level of signal performance across the house and building,” Daniel Cooley, Senior Vice President of Silicon Labs, told Digital Trends. “People won’t put up with flaky Wi-Fi anymore. If they can get away with fewer antennas, it would be much better.” Cooley is a member of the Bluetooth Special Interest Group, or SIG, which oversees and develops Bluetooth technology. If he’s right—and industry watchers and makers of networking equipment are betting that he is—many aspects of our lives will soon be secured and simplified by this latest Bluetooth update. Traditional wireless networks, including one-to-one Bluetooth networks, are limited by distance between the two devices communicating. Wi-Fi makes that worse with an additional impediment—relatively high-power requirements. It’s difficult to make a Wi-Fi signal extend more than a few hundred feet without a massive antenna and large power supply. Bluetooth Mesh devices find a clever way to fix that.  They connect to each other, and pass signals to peers that are within range, forming a web, or mesh, of interconnected devices capable of relaying data. This means that information is passed from one device to another, and another, and so on. This “managed flood” approach to data transmission, according to the Bluetooth SIG, “is uniquely suited for low-power wireless mesh networks, especially those handling a significant amount of multicast traffic.” “Multicast” is a form of network communication where a single sender broadcasts to multiple receivers. In a “flood network,” every device in the chain, or mesh, is multicasting to every device within its range, and so on. That creates a reliable network without the need for massive power draw or a big, beefy antennas. How Bluetooth Mesh works An important component of the Bluetooth protocol is its Generic Access Profile, or GAP, which controls how Bluetooth devices scan, broadcast, and connect to their peers. Until Bluetooth Mesh, GAP had a typical parent-child network relationship, where the parent did all the routing, and the child performed its allotted task. That’s what happens when you connect a Bluetooth keyboard to your tablet, for example. Ref.KY45-TMP421YZDRKY45-AD7814ARMZ

In autumn, an abundance of fallen leaves from deciduous phoenix trees are scattered around the streets in Northern China. These leaves are generally burned in the colder season, exacerbating the country's air pollution problem.Investigators in Shandong, China, recently discovered a new method to convert this organic waste matter into a porous carbon material that can be used to produce high-tech electronics. The advance is reported in the Journal of Renewable and Sustainable Energy, by AIP Publishing. The investigators used a multistep, yet simple, process to convert tree leaves into a form that could be incorporated into electrodes as active materials. The dried leaves were first ground into a powder, then heated to 220 degrees Celsius for 12 hours. This produced a powder composed of tiny carbon microspheres. These microspheres were then treated with a solution of potassium hydroxide and heated by increasing the temperature in a series of jumps from 450 to 800 C. The chemical treatment corrodes the surface of the carbon microspheres, making them extremely porous. The final product, a black carbon powder, has a very high surface area due to the presence of many tiny pores that have been chemically etched on the surface of the microspheres. The high surface area gives the final product its extraordinary electrical properties.(Scanning Electron Microscopy (SEM) image of porous carbon microspheres.)The investigators ran a series of standard electrochemical tests on the porous microspheres to quantify their potential for use in electronic devices. The current-voltage curves for these materials indicate that the substance could make an excellent capacitor. Further tests show that the materials are, in fact, supercapacitors, with specific capacitances of 367 Farads/gram, which are over three times higher than values seen in some graphene supercapacitors. A capacitor is a widely used electrical component that stores energy by holding a charge on two conductors, separated from each other by an insulator. Supercapacitors can typically store 10-100 times as much energy as an ordinary capacitor, and can accept and deliver charges much faster than a typical rechargeable battery. For these reasons, supercapacitive materials hold great promise for a wide variety of energy storage needs, particularly in computer technology and hybrid or electric vehicles. This research is led by Hongfang Ma of Qilu University of Technology, and has been heavily focused on looking for ways to convert waste biomass into porous carbon materials that can be used in energy storage technology. In addition to tree leaves, the team and others have successfully converted potato waste, corn straw, pine wood, rice straw and other agricultural wastes into carbon electrode materials. Professor Ma and her colleagues hope to improve even further on the electrochemical properties of porous carbon materials by optimizing the preparation process and allowing for doping or modification of the raw materials. The supercapacitive properties of the porous carbon microspheres made from phoenix tree leaves are higher than those reported for carbon powders derived from other biowaste materials. The fine scale porous structure seems to be key to this property, since it facilitates contact between electrolyte ions and the surface of the carbon spheres, as well as enhancing ion transfer and diffusion on the carbon surface. The investigators hope to improve even further on these electrochemical properties by optimizing their process and allowing for doping or modification of the raw materials.  This article is authored by Hongfang Ma, Zhibao Liu, Xiaodan Wang and Rongyan Jiang and is published in Journal of Renewable and Sustainable Energy.  Ref.KY36-5KK560KOAAM(capacitor)KY36-DEBB33F222KA3B(capacitor)KY605-NH12VP(rechargeable battery)  

The rapid development of wearable technology has received another boost from a new development using graphene for printed electronic devices. New research from The University of Manchester has demonstrated flexible battery-like devices printed directly on to textiles using a simple screen-printing technique. The current hurdle with wearable technology is how to power devices without the need for cumbersome battery packs. Devices known as supercapacitors are one way to achieve this. A supercapacitor acts similarly to a battery but allows for rapid charging which can fully charge devices in seconds. Now a solid-state flexible supercapacitor device has been demonstrated by using conductive graphene-oxide ink to print onto cotton fabric. As reported in the journal 2D Materials the printed electrodes exhibited excellent mechanical stability due to the strong interaction between the ink and textile substrate. Further development of graphene-oxide printed supercapacitors could turn the vast potential of wearable technology into the norm. High-performance sportswear that monitors performance, embedded health-monitoring devices, lightweight military gear, new classes of mobile communication devices and even wearable computers are just some of the applications that could become available following further research and development. To power these new wearable devices, the energy storage system must have reasonable mechanical flexibility in addition to high energy and power density, good operational safety, long cycling life and be low cost. Dr Nazmul Karim, Knowledge Exchange Fellow, the National Graphene Institute and co-author of the paper said: "The development of graphene-based flexible textile supercapacitor using a simple and scalable printing technique is a significant step towards realising multifunctional next generation wearable e-textiles." "It will open up possibilities of making an environmental friendly and cost-effective smart e-textile that can store energy and monitor human activity and physiological condition at the same time". Graphene-oxide is a form of graphene which can be produced relatively cheaply in an ink-like solution. This solution can be applied to textiles to create supercapacitors which become part of the fabric itself. Dr Amor Abdelkader, also co-author of the paper said: "Textiles are some of the most flexible substrates, and for the first time, we printed a stable device that can store energy and be as flexible as cotton. "The device is also washable, which makes it practically possible to use it for the future smart clothes. We believe this work will open the door for printing other types of devices on textile using 2D-materials inks." The University of Manchester is currently completing the construction of its second major graphene facility to complement the National Graphene Institute (NGI). Set to be completed 2018, the £60m Graphene Engineering Innovation Centre (GEIC) will be an international research and technology facility. The GEIC will offer the UK the unique opportunity to establish a leading role in graphene and related 2D materials. The GEIC will be primarily industry-led and focus on pilot production and characterisation. Ref.MS614SE-FL28EML-614S/FN

As we can know, a new technique that can change plastic's molecular structure to help it cast off heat is a promising step in that direction. Advanced plastics could usher in lighter, cheaper, more energy-efficient product components, including those used in vehicles, LEDs and computers -- if only they were better at dissipating heat. Developed by a team of University of Michigan researchers in materials science and mechanical engineering and detailed in a new study published in Sciene Advances, the process is inexpensive and scalable. The concept can likely be adapted to a variety of other plastics. In preliminary tests, it made a polymer about as thermally conductive as glass -- still far less so than metals or ceramics, but six times better at dissipating heat than the same polymer without the treatment."Plastics are replacing metals and ceramics in many places, but they're such poor heat conductors that nobody even considers them for applications that require heat to be dissipated efficiently," said Jinsang Kim, U-M materials science and engineering professor. "We're working to change that by applying thermal engineering to plastics in a way that hasn't been done before." The process is a major departure from previous approaches, which have focused on adding metallic or ceramic fillers to plastics. This has met with limited success; a large amount of fillers must be added, which is expensive and can change the properties of the plastic in undesirable ways. Instead, the new technique uses a process that engineers the structure of the material itself. Plastics are made of long chains of molecules that are tightly coiled and tangled like a bowl of spaghetti. As heat travels through the material, it must travel along and between these chains -- an arduous, roundabout journey that impedes its progress. The team -- which also includes U-M associate professor of mechanical engineering Kevin Pipe, mechanical engineering graduate researcher Chen Li and materials science and engineering graduate student Apoorv Shanker -- used a chemical process to expand and straighten the molecule chains. This gave heat energy a more direct route through the material. To accomplish this, they started with a typical polymer, or plastic. They first dissolved the polymer in water, then added electrolytes to the solution to raise its pH, making it alkaline. The individual links in the polymer chain -- called monomers -- take on a negative charge, which causes them to repel each other. As they spread apart, they unfurl the chain's tight coils. Finally, the water and polymer solution is sprayed onto plates using a common industrial process called spin casting, which reconstitutes it into a solid plastic film. The uncoiled molecule chains within the plastic make it easier for heat to travel through it. The team also found that the process has a secondary benefit -- it stiffens the polymer chains and helps them pack together more tightly, making them even more thermally conductive. "Polymer molecules conduct heat by vibrating, and a stiffer molecule chain can vibrate more easily," Shanker said. "Think of a tightly stretched guitar string compared to a loosely coiled piece of twine. The guitar string will vibrate when plucked, the twine won't. Polymer molecule chains behave in a similar way." Pipe says that the work can have important consequences because of the large number of polymer applications in which temperature is important. "Researchers have long studied ways to modify the molecular structure of polymers to engineer their mechanical, optical or electronic properties, but very few studies have examined molecular design approaches to engineer their thermal properties," Pipe said. "While heat flow in materials is often a complex process, even small improvements in the thermal conductivities of polymers can have a large technological impact." The team is now looking at making composites that combine the new technique with several other heat dissipating strategies to further increase thermal conductivity. They're also working to apply the concept to other types of polymers beyond those used in this research. A commercial product is likely several years away. "We're looking at using organic solvents to apply this technique to non- water soluble polymers," Li said. "But we believe that the concept of using electrolytes to thermally engineer polymers is a versatile idea that will apply across many other materials." Ref.KY59-GW5BTF50K00KY59-LMR040-0700-40F8-20100EW

Washington State University physicists have found a way to write an electrical circuit into a crystal, opening up the possibility of transparent, three-dimensional electronics that, like an Etch A Sketch, can be erased and reconfigured. The work, to appear in the on-line journal Scientific Reports, serves as a proof of concept for a phenomenon that WSU researchers first discovered by accident four years ago. At the time, a doctoral student found a 400-fold increase in the electrical conductivity of a crystal simply by leaving it exposed to light. Matt McCluskey, a WSU professor of physics and materials science, has now used a laser to etch a line in the crystal. With electrical contacts at each end of the line, it carried a current. "It opens up a new type of electronics where you can define a circuit optically and then erase it and define a new one," said McCluskey. "It's exciting that it's reconfigurable. It's also transparent. There are certain applications where it would be neat to have a circuit that is on a window or something like that, where it actually is invisible electronics." Ordinarily, a crystal does not conduct electricity. But when the crystal strontium titanate is heated under the right conductions, it is altered so light will make it conductive. The phenomenon, called "persistent photoconductivity," also occurs at room temperature, an improvement over materials that require cooling with liquid nitrogen. "We're still trying to figure out exactly what happens," said McCluskey. He surmises that heat forces strontium atoms to leave the material, creating light-sensitive defects responsible for the persistent photoconductivity. McCluskey's recent work increased the crystal's conductivity 1,000-fold. The phenomenon can last up to a year. "We look at samples that we exposed to light a year ago and they're still conducting," said McCluskey. "It may not retain 100 percent of its conductivity, but it's pretty big." Moreover, the circuit can be by erased by heating it on a hot plate and recast with an optical pen. "It's an Etch A Sketch," said McCluskey. "We've done it a few cycles. Another engineering challenge would be to do that thousands of times." The research was funded by the National Science Foundation. Co-authors on the paper are former students Violet Poole and Slade Jokela. The work is in keeping with WSU's Grand Challenges, a suite of initiatives aimed at addressing large societal problems. It is particularly relevant to the challenge of Smart Systems and its theme of foundational and emergent materials. Ref.KY163-NX1255GBKY163-TSX-3225