- Chipless RFID replaces silicon chips with passive electromagnetic structures embedding unique IDs.
- The technology enables contactless identification without direct line of sight, unlike barcodes and QR codes.
- Cost savings derive from eliminating semiconductor manufacturing complexities and reducing material use.
- Challenges remain in enhancing data capacity, reliable signal detection, and standardizing system interfaces.
Ines Bakri, a doctoral candidate at RheinMain University of Applied Sciences (HSRM) in the field of IoT and Digital Communication Technology, explains how chipless RFID enables identification without a silicon chip. The focus is on the current state of research, the technical potential, and the question of why passive structures could be a scalable alternative to traditional RFID tags for mass applications in logistics, packaging, and industry.
The technology is particularly relevant for applications involving very high volumes, such as in logistics with a large number of pallets, load carriers, or other reusable objects. Today, these are often tracked via direct line of sight. Chipless RFID could enable contactless identification in these scenarios and simplify repeated tracking throughout logistics processes.
How It Works and a Shift in Technological Perspective
Technologically, chipless RFID is closely related to printed electronics. Instead of a silicon chip, the tag uses passive structures such as resonators or printed patterns that can be applied to films, paper, or packaging. These structures do not store data in the traditional sense, but rather generate an electromagnetic signature that can be detected by a reader and translated into an ID.
Bakri makes it clear that the information is no longer stored in a silicon IC, but rather lies in the physical design of the tag. This is precisely where the shift in technological perspective lies: intelligence moves from the chip to the structure. If the pattern is produced using a printing process, chipless RFID becomes a particularly simple form of functional printed electronics.
Potential, Challenges, and Research Needs
From Ines Bakri’s perspective, chipless RFID is particularly interesting for applications in which a very large number of objects need to be identified cost-effectively. Eliminating the need for silicon can lower material costs, conserve resources, and reduce dependence on global chip supply chains.
At the same time, important research questions remain unanswered. These include higher storage capacities, more robust detection methods, reliable reading in complex environments, and standardized interfaces to existing RFID and IoT systems.
Object Identification Beyond the Semiconductor Supply Chain
In the context of chipless RFID, it is crucial to note that it is not the extraction of silicon that represents the largest cost and resource factor, but rather its purification, processing, and conversion into electronic components.
Eliminating the use of silicon chips can therefore be economically significant, particularly for very large production volumes. The savings come not merely from raw materials like “sand,” but also from the complex semiconductor manufacturing process, additional materials, energy, assembly costs, and parts of the associated supply chain.
However, the technology can also offer advantages even with smaller production volumes. Passive, chipless structures are potentially suitable for applications where traditional electronic components reach their limits due to high temperatures, humidity, weather conditions, or other demanding environmental factors. At the same time, they can enable the contactless identification of objects that, until now, could often only be detected through direct line of sight.
Chipless RFID could thus partially shift dependencies in object identification. While traditional RFID tags rely on silicon chips and the globally diversified semiconductor industry, chipless systems are based on passive, structured tags. The chip, as a critical component, is eliminated.
This can be particularly relevant for mass applications as well as for reusable objects such as pallets, load carriers, or industrial components. However, this does not make the technology completely independent of supply chains. Chip manufacturing is replaced by requirements for suitable materials, precise printing and manufacturing processes, high-performance reader hardware, and standardized interfaces.
Range of Chipless RFID
The range of chipless RFID is not strictly defined but depends heavily on the tag design, the frequency range, the reader or radar system, and the environment. In simple experimental setups, distances often range from a few centimeters to about one meter. For long-range applications, however, research is underway to reliably detect chipless tags even over distances of several meters.
The key technological factor here is the tag’s backscatter. The reading system transmits an electromagnetic signal that is reflected by the chipless tag. This backscatter contains the tag’s characteristic electromagnetic signature. The stronger and more distinct this signature is, the greater the distance between the reader and the tag can be.
Lecture by Ines Bakri: Understanding Chipless RFID
Chipless RFID technology enables scalable and cost-effective identification through electromagnetic signatures, offering a promising alternative to silicon chip-based methods despite current technical challenges.
The potential range is limited by several factors: the size and geometry of the resonator structures, the tag’s radar cross section, the reader’s transmit power and sensitivity, the antenna gain, the frequency range used, and interference from metal, liquids, or multipath propagation in real-world environments. Especially in industrial and logistics environments, reflections can interfere with the signal and make detection more difficult.
For longer distances, therefore, techniques such as MIMO systems, optimized antennas, robust detection algorithms, and intelligent signal processing are employed. The goal is to detect weak backscatter signals more reliably, separate the tag’s signature from environmental reflections, and thereby enable long-range applications as well.
In short: Chipless RFID can work relatively easily at close range. For longer ranges in the meter range, however, an optimized overall system comprising tag design, reader hardware, antennas, and signal processing is required.
At first glance, chipless RFID sounds like a highly technical, specialized solution. How can you explain simply how this technology works?
M.Eng. Ines Bakri: At its core, chipless RFID works without a traditional microchip. Instead, the tag consists of passive structures—such as resonators or special patterns—that can be printed onto a film or other substrate. These structures respond to electromagnetic signals in a very distinctive way.
Where is the information stored if there is no chip?
M.Eng. Ines Bakri: The information is embedded in the tag’s physical structure. Each pattern generates a unique electromagnetic signature—for example, a specific frequency or phase pattern. This signature can be read and then translated into binary code. Thus, each tag configuration represents a unique ID.
Can chipless RFID tags store just as much information as traditional RFID tags with a memory chip?
M.Eng. Ines Bakri: No, not in the same way. If they have memory, traditional RFID tags can contain significantly more information than just an ID. Chipless RFID does not have such memory. The information is encoded in the tag’s structure. This allows for unique IDs and a limited amount of additional information.
Sensor applications are possible, but they work differently: The tag does not actively store measurement values; instead, its electromagnetic signature changes in response to temperature, humidity, pressure, or other factors.
How does a reader detect this ID?
M.Eng. Ines Bakri: Detection works similarly to radar. A reader emits an electromagnetic signal. When this signal hits the chipless RFID tag, it is reflected or backscattered by the tag. The backscattered signal is then analyzed. This reveals whether a tag is present and what ID it contains.
What is the most important difference from traditional RFID technology?
M.Eng. Ines Bakri: The key difference is that chipless RFID does not require a silicon chip. Traditional RFID tags typically contain an integrated circuit that stores and processes information. With chipless RFID, the tag’s structure itself performs this function.
Why is eliminating the chip an advantage?
M.Eng. Ines Bakri: Because it can reduce material and manufacturing costs. Additionally, no complex connections between the chip and the antenna are necessary. This makes the tags simpler in design.
What role does durability play?
M.Eng. Ines Bakri: Chipless RFID tags can be very robust because they operate passively and do not require their own power supply. They can be designed to be weather-resistant and integrated into flexible materials, labels, or packaging. This can be a major advantage, especially for industrial applications, logistics processes, or mass labeling.
How does chipless RFID differ from barcodes or other camera-based identification systems?
M.Eng. Ines Bakri: The most important difference is that chipless RFID does not require a direct line of sight. While barcodes or QR codes must be scanned optically, a chipless RFID tag can be read even when it is obscured, for example, under packaging or certain materials.
What does this mean for practical applications?
M.Eng. Ines Bakri: The technology can also offer advantages in low light, when surfaces are dirty, or when they are damaged. Camera-based systems are heavily dependent on the code being visible and easily readable. With chipless RFID, on the other hand, identification is performed via electromagnetic signals.
Is the technology also cost-effective?
M.Eng. Ines Bakri: Yes. The reading systems are based on RF hardware and do not require complex optics or elaborate image processing. Depending on the application, this can simplify the system architecture and reduce costs.
What needs to happen for chipless RFID to be deployed on a large scale?
M.Eng. Ines Bakri: Concrete use cases and pilot projects are crucial. The technology must demonstrate in real-world conditions across industry, logistics, and manufacturing where it works reliably and what added value it offers. This can lead to the development of best-practice scenarios.
What technical challenges remain?
M.Eng. Ines Bakri: An important goal is to increase storage capacity and data density. The aim is to be able to store more IDs—or more bits—per day and to read the data more reliably. Higher data rates may also become relevant, depending on the application.
What role do environmental disturbances play?
M.Eng. Ines Bakri: A very significant one. Electromagnetic signals can be affected by surrounding objects, reflections, or so-called multipath effects. That’s why the robustness of the systems must be further improved so that tags can be reliably detected even in complex industrial environments.
Are standards also needed for this?
M.Eng. Ines Bakri: Yes. Standardized protocols and interfaces are essential for widespread adoption. Chipless RFID must be able to integrate seamlessly into existing RFID and IoT systems. Only when companies can easily incorporate the technology into their existing processes will it become truly attractive for large-scale deployment.
Biography: Ines Bakri
Since 2024, Ines Bakri has been pursuing her Ph.D. at the Rüsselsheim campus of RheinMain University of Applied Sciences in the field of IoT and digital communication technology. Her doctoral research is supervised by Prof. Mohamed El Hadidy, an IEEE Senior Member and internationally recognized expert in chipless RFID with numerous publications in this field of research.
Ines Bakri conducts her research as part of a team of five doctoral candidates who are investigating various subfields of chipless RFID systems. These include localization, AI-assisted detection, tag design, beamforming networks, IoT connections, and other aspects of system development and signal processing.
In her master’s thesis, she developed a chipless RFID identification system for realistic communication channels, focusing on channel modeling, frequency sweeping, reader implementation, and blind detection.
Her current research focuses on chipless RFID systems, detection algorithms, channel modeling and system emulation, MIMO communication systems, as well as indoor positioning, localization, and navigation. To date, she has contributed to six IEEE publications. Another publication has been submitted, and she is also working on her first journal article.
In addition, Ines Bakri is a co-founder and chair of the IEEE Student Branch at RheinMain University of Applied Sciences.
