Johan Sidén

Designing of RFID-Based Sensor Solution for Packaging Surveillance Applications

In this work, a two-chip battery assisted Radio Frequency Identification (RFID) based sensor platform is presented. The radio frequency communication interface is based on the EPC Gen 2 standard. A laboratory setup of the platform has been shown and characterized for a moisture content sensor application. The laboratory setup of the sensor platform has a reading range of 3.4 meters which is in comparison to commercial available Gen 2 tags. The laboratory platform has an average power consumption of 2.1 μW operating at 3 V, which together with a printed battery gives an estimated lifetime for data logging of several years. The proposed RFID platform provides a tradeoff between, communication performance, compatibility with international standards, and flexibility in on-package customization including type and number of sensors. The proposed architecture separates the high-performance communication circuit and the low-frequency sensor interface logic. In the future, the sensor interface maybe integrated using printed logics to further enhance the flexibility and low-cost customization features of the architecture.

System Integration of Electronic Functions in Smart Packaging Applications

A system integration scheme relevant for smart packaging applications is presented. Recent advances in printed electronics, radio frequency identification tag production, and standardization of communication protocols are factors that increase the design freedom for new applications. As in all new technology fields, the first products are expected to appear in the high-cost segment attracting early adopters in the form of niche products. A reasonable assumption is that these products will come from hybridization of different types of technologies. Such a scenario is likely since no technology solution available can provide all features that these types of applications demand. There is a need of standard solutions for hybridization of silicon devices and printed (or foil-type) components. Conductive ink technology is a powerful tool for hybridization and customization of large-area electronics, providing 3-D integration and large-area customization. However, high-performance communication and advanced processing demand the use of silicon. Smart hybridization solutions allow combination of the best from both worlds. This paper analyzes the requirements on hybridization technologies suitable for smart packaging applications and provides design examples on integration of intrusion surveillance solutions for cellulose-based packaging applications. It shows that even though the current hybridization technologies are far from optimal, they can provide a considerable design freedom and system performance.

Reduced Amount of Conductive Ink with Gridded Printed Antennas

It becomes more and more common to print tag antennas using electrically conductive ink for mass-produced Radio Frequency IDentification (RFID) tags. Electrical properties of the ink are mostly determined by conductive (e.g. silver) particles mixed into the ink solution. Since silver is relatively expensive it is desirable to minimize the amount of ink used per antenna. This paper illustrates how the printed conductor area of the antenna can be reduced by applying a grid pattern to an existing antenna geometry and to what extent the gridding can be performed without significantly degrading of the antenna electrical properties. Two common antenna structures are used as an example. It is also shown that by slightly modifying the original antenna geometry it is possible to even further reduce the amount of used ink.

Performance degradation of RFID system due to the distortion in RFID tag antenna

In some Radio-Frequency IDentification (RFID) applications, the RFID tag antennas will be printed onto flexible substrates. After sticked onto different objects, possible distortion to the tag antenna such as bending of the tag will be caused due to the flexibility. In this paper, performance degradation of passive RFID systems due to bending of the RFID tag antenna is investigated. The antenna used is the basic folded dipole. Simulation results show that the performance of a passive RFID system, characterized by operating range, can be degraded significantly due to distortion. Thus, antenna structures less sensitive to this should be considered for RFID systems where this kind of effect might occur.

Line width limitations of flexographic-screen- and inkjet printed RFID antennas

As RFID tags are now being produced in very large amounts there is a great desire to simplify their construction by printing the antennas using electrically conductive ink. Printed antennas from silver-based inks can provide almost the same efficiency as their corresponding copper antennas and there are several ways to accomplish the printing process. Different printing processes all have their advantages and disadvantages. As silver, when used as a conductive material, is naturally more expensive than copper, this is the reason that it is important to minimize the amount used per antenna. This article presents a study of the limitations in a minimum line width for flexographic-, screen-, and inkjet printed RFID antennas.

The "smart" diaper moisture detection system

Smart diaper moisture detection system described is a paper-based disposable moisture-activated RFID system that could be incorporated into the traditional cellulose-based diaper. The tag is semi-passive in the sense that it has no internal battery but incorporates a built-in energy conversion sensor (Action-Activated Tag). The tag with sensor unit is optimized for low-cost manufacturing, utilizes screen-printing with electrically conductive ink on paper-based substrates and inherits very low EM radiation. A discussion on the manufacturability and cost efficiency of the system is presented. A prototype system is shown and other possible application areas of the system are mentioned.

Printed Electromagnetic Coupler With an Embedded Moisture Sensor for Ordinary Passive RFID Tags

This letter presents a printed UHF RFID sensor solution that indicates if a passive RFID tag has been exposed to a certain degree of moisture. The printed sensor operates as a write-once-read-many (WORM) resistive memory device as it permanently changes its resistance from about 10 kΩ to 10 Ω after exposure to moisture or water. A printed coupling loop with an embedded WORM sensor is horizontally placed just above the surface of an ordinary UHF RFID tag. Electromagnetic coupling is used to modulate the properties of the tag antenna by changing its input impedance and introducing ohmic losses in proportion to the embedded sensor values. The passive RFID tag can change state from readable to unreadable when the WORM bit is set, i.e., is put in a low-resistance state. The proposed concept verifies that commercial RFID tags can be used as sensor tags by simply adding an electromagnetically coupled sensor as a sticker or by similar means, without the need for ohmic contacts between the sensor and the original RFID tag.

Printed Write Once and Read Many Sensor Memories in Smart Packaging Applications

A horizontal printed Write-Once-Read-Many (WORM) resistive memory has been developed for use in wireless sensor tags targeting single-event detection in smart packaging applications. The WORM memory can be programmed using a 1.5-V printed battery. An alternative programming method is to use chemical sintering which allows the development of exposure-time triggered single event tags that can be accessed wirelessly. The new WORM memory has very low losses in the ON-state which allows direct integration into antenna structures. A sensor tag that utilizes the WORM memory functionality and the well established Electronic Article Surveillance (EAS) communication standard has been outlined. Both active and fully passive sensor tag solutions have been proposed. The role of printed electronics in smart packaging applications has been reviewed and discussed. Important enabling factors for the future development have been highlighted, such as the need for hierarchical design and test tools, better printed interconnect technologies as well as better components that allow communication with existing information and communication technology (ICT) standards. This is illustrated and underlined by the presented smart packaging concept demonstrators.

Assembling surface mounted components on ink-jet printed double sided paper circuit board

Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed.

A Distanced RFID Dipole for a Metallic Supply Chain Label

This paper presents a low cost solution for integration of RFID tags with dipole antennas onto traditional metal labels. Metal labels of this shape are used in a hardware supply chain and covered with a plastic layer where information is printed upon it. The RFID tag is a complement to the printed information that goes into the same label and is put away from the metallic surface with the aid of a 10 mm polyurethane foam (foam rubber) spacer that due to its high flexibility have potential to be run through the usual label printer