RFID for Container Tracking has become a game-changer in logistics. Radio Frequency Identification Technology (RFID), favored by the container transport industry for its fast identification speed, high accuracy, contactless operation, and strong environmental adaptability, is now rapidly expanding. It is widely adopted in transportation, air parcel management, logistics, production line automation, access control, material handling, healthcare, and beyond.
The RFID technology in to the tray, the container, the transportation vehicles and so on the aspect management, to the commodity labeling as well as the supply chain whole management application has promoted the development of the logistics industry. The electronic label has the reading distance far (generally within 20 m), is suitable for the bad environment, the penetration is strong, can recognize the movement target and so on the characteristic.
The RFID technology in the container domain application makes the accurate control, the tracking container who, where, when information becomes possible. Container with electronic tags with ultra-high frequency (UHF) band. This frequency band’s penetration ability is strong, and in the dynamic reading shows the superiority. Relative to the industrial automation and other fields of application, the electronic label in the container logistics and transportation in the application of a strong particularity. rfid tag with the container in the sea, wharf, yard and other places flow, its working environment has a big temperature difference, ultraviolet irradiation intensity, seawater on the label has corrosive and other characteristics of the container with the rfid tag packaging must consider these factors. At the same time, the container metal surface of the electromagnetic wave reflection effect on the data transmission is extremely influential. Under the influence of the metal surface, the original matching antenna becomes mismatched, and it is necessary to redesign the antenna and reimpedance matching.
1. Introduction to the working principle of RFID
RFID is a use of radio frequency signals through spatial coupling (alternating magnetic field or electromagnetic field) to achieve contactless information transfer and through the information transferred to achieve the purpose of identification technology. His core component is an electronic tag, through the distance of a few centimeters to a few meters or even a dozen meters away from the read-write transmit radio waves, read the electronic tag within the stored information. Passive RFID tags are read-write to send the radio frequency energy into DC power supply for the chip circuit power supply.
Anti Metal UHF RFID Tag Factory
2.The electronic label applies in the container domain the problem which appears
The container transportation environment to the electronic label application performance index influence
Relative to the industrial automation and so on the domain application, the electronic label in the container logistics transportation application has the very strong speciality.
2.1 the working environment is comparatively bad
- The electronic label flows with the container in the sea, the wharf, the yard and so on the place, and the ordinary electronic label working environment is different. Label in the design and packaging must consider the following factors:
- Temperature specificity: the container working environment temperature is high, the temperature difference is big, and the operation is all-weather.
- The high humidity working environment: The container transportation process most of the time in the sea (or inland waterway) completes, therefore the electronic label must be able to in the humidity is 35% ~ 80% of the environment work.
- The strong ultraviolet ray irradiation: The long time, the high intensity ultraviolet ray irradiation accelerates the label shell plastic aging.
- Acid and alkali corrosion and vibration impact: container most of the time are working in the dock, the sea, this environment requires labeling resistance to acid and alkali corrosion, at the same time packaging structure and materials to resist vibration impact.
2.2 label dynamic reading
Because the container circulation speed is fast, the container information must be able to access from a long distance, therefore, requests the electronic label to recognize the speed is high (the movement speed >100 km/h), the distance is far (>6 m), the accuracy rate is high (>99%) and so on.
2.3 Container with the electronic label by the metal surface of the impact of analysis
Ordinary RFID tag directly attached to the metal surface, due to the metal surface of the incident electromagnetic wave reflection effect, there will be a strong reverse direction electromagnetic wave also through the electronic tag. Incident wave and reflected wave phase superposition will offset part of the intensity will be greatly weakened, seriously affecting the read-write on the RFID tag reading distance, and even can not read and RFID tags on the data. At the same time, read-write and RFID tags generated between the magnetic flux will be in the metal surface induced eddy currents, according to corrugated law, eddy currents on the read-write’s magnetic field to play an opposite role, resulting in a strong attenuation of the magnetic field on the metal surface.
Custom Anti Metal RFID Tag
The solution to eliminate the effect of the metal surface of the container is to increase the relative height of the antenna and the metal surface. As the relative height increases, the synthetic field signal vector will gradually enhance, to the relative height of 1/4 of the wavelength, the synthetic field signal vector reaches the maximum, and can obtain 3 dB gain. RFID tags attached to the metal surface of the container, the distance between the tag and the metal surface is very small, can be raised to a limited space, can not meet the requirements. For example: 900 MHz RF 1/4 wavelength approximation for 8 cm, and the container outer surface groove actual depth is only 2 cm. need to insert a kind of isolation medium between the ordinary electronic tags and the metal surface, according to the wavelength of electromagnetic wave in the medium formula:
Where: λ0 is free space wavelength, μ, ε are medium permeability and dielectric coefficient respectively.
The usual practice is to encapsulate the isolation medium and the electronic label into a single unit, thus forming an anti-metal electronic label. The research that needs to be done includes the study of the medium (medium selection, test and process determination, etc.), data analysis of specific medium parameters (μ, ε, etc.), and the choice of encapsulation form.
Considering the influence of metal to the electronic tag antenna design
Label antenna characteristics by the shape and physical properties of the marked object, the label to the labeling object of the distance, labeling object of the dielectric constant, the reflection of the metal surface and the isolation of the media parameters and so on. Therefore, the ordinary label attached to the metal surface of the container, the original matching antenna becomes no longer match, the need to redesign the antenna, determine the antenna geometry and size. UHF RFID tag antennas are generally long and tag-like, while the antenna has two designs of linear and circular polarization [2] to meet the needs of different applications.
Ordinary electronic tag antenna size is extremely small, but the large space of the container body relaxes the requirements of the electronic tag antenna size. At the same time the antenna design must consider the effect of the isolation medium mentioned earlier. The goal of the antenna design is to transmit the maximum energy in and out of the circuit, the higher the degree of antenna matching, the better the antenna radiation performance. This requires careful design of the antenna and free space and chip circuit matching. the UHF wave band electronic label antenna is generally used in the form of microstrip antenna. In the traditional microstrip antenna design, we can control the antenna size and structure, or use the impedance matching converter to make its input impedance and feed line matching. The electronic label chip impedance generally presents strong sense and weak resistance characteristics, and it is difficult to measure the accurate impedance characteristics of the chip working state data. Its input impedance, direction map and other characteristics are easily affected by the processing accuracy, the purity of the dielectric board. In maintaining the antenna performance at the same time to make the antenna and the chip match, taking into account the influence of the metal surface of the container, this is the container with the electronic label antenna design of a major difficulty. In previous studies, it is generally believed that the antenna can be realized by using a wide bandwidth antenna to match the antenna and the chip.
3. Introduction to the electronic label packaging process
- due to the RFID tag chip tiny ultra-thin, the method used is flip chip (Flip Chip) technology, automated assembly line are selected from the volume to volume of the production mode, the process includes substrate feeding, gluing, chip flip mounting, hot pressing curing, testing, substrate receiving and other processes. He has high performance, low cost, miniaturization, high reliability. But the process equipment is expensive, generally need to use the equipment of foreign manufacturers to carry out.
- Another encapsulation is the first chip and antenna substrate bonding package is divided into two modules to complete. One of the specific practices (China Patent) is: large size antenna substrate and connect the chip of the small piece of substrate manufacturing, in the small piece of substrate to complete the chip mounting and interconnection, and then with the large size antenna substrate through the adhesion of the large pads to complete the circuit conduction. The method by independent precision positioning chip transfer equipment will be placed on the chip carrier tape constitute a chip module, and then transfer the chip module to the antenna substrate, the advantage is that the two transfers can be carried out independently and in parallel.
At present, flip-flop technology is more mature label packaging technology. This encapsulation technology has a simple encapsulation procedure, mature technology, low cost, encapsulated tags are small, ultra-thin, easy to paste the advantages. Common labels on the market are mostly used in this process. But this equipment is expensive, currently in the country can carry out flip-flop manufacturers are minimal. More than the second, the chip and antenna precision welding to achieve the purpose of connection. Relative to the first, this technology requires a lot less equipment, but the encapsulation process is time-consuming.
4. Applicable to the container with the electronic label packaging process to explore
The actual application of most of the label package size and form by the labeled object limitations, the general situation of the label to do small and thin, can be packaged into a card twice. And the surface area of the container box is very large, relaxing the surface area and volume requirements of the label. This is very favorable to the design of the tag antenna. Because many cases by the limitations of the volume of the labeled object, the volume of the label to be very small, its induction antenna is bound to be smaller, in the same field strength, the small antenna senses the electrical energy than the big antenna to be much weaker. Container with the electronic label dynamic reading request reads the distance comparatively far (about 10 m), therefore to the antenna size request higher, because the size smaller antenna in the distance read-write is very close when presents the higher field strength, but the larger antenna in the farther distance the field strength is still comparatively high. Therefore the container with the electronic label can be made bigger, finally encapsulated into the box, fixed in the container surface. Need not be made into flexible, paper, stickable.
According to the actual needs of the electronic label labeling container, flip-flop process made of paper labels can not meet the container working environment of anti-vibration, corrosion resistance and other aspects of the requirements, and there is no need to label the volume of the package is very thin, in view of the domestic level of encapsulation technology can be in the chip and the antenna before welding the chip for the TSSOP package, and lead out the required pins. Based on this, the use of China’s patented technology to achieve the interconnection of the chip and antenna, the process of chip packaging and antenna substrate bonding package is divided into two modules to complete. Then media filling, shell sealing, and finally made into a container electronic tag finished product, and high-temperature aging, testing, packaging. In this process, the use of the environment is taken into account on the metal surface reflection, waterproof, moisture-proof, anti-fog, lightning and other indicators required.
After TSSOP packaging of the chip, the pins are bonded to the antenna, which solves the problem of expensive inverted packaging equipment and dependence on foreign technology. And compared with the previous two forms of packaging tags, TSSOP packaging materials with pressure, high temperature resistance and other characteristics, to meet the higher requirements of the container operating environment, improve the reliability and stability of the label. The entire label package compared with the flexible package, because it has a media filler, to solve the problem of container metal face labeling impact. And the sealed shell can meet the temperature difference, humidity, acid, alkali and salt spray corrosive, vibration impact and other aspects of the requirements.
5. Conclusion
At present our country’s radio frequency identification technology is still in a beginning stage, will RFID technology used to container industry has a very optimistic prospect, however, the application of electronic tags in the container industry on the application of a great deal of specificity. This paper through the research, explains in the metal surface interference situation, the antenna design and impedance matching should be considered many problems, pointed out his design direction, explains the electronic label package can break through the traditional electronic label package form, choose a suitable container application environment of the package, through the filling of the dielectric material to solve the problem of metal surface interference. Along with the electronic label technology’s maturity, his application field will expand unceasingly, not long from now on the traveling container vehicle can tell the traffic management system own specific position, a train full of goods passes, the roadside sensor will show the car loaded with goods the kind, the quantity and so on.
6.Frequently Asked Questions
6.1 How does RFID improve container tracking compared to traditional methods?
RFID enables:
✓ Real-time visibility (vs manual scans/paper logs)
✓ 99.9% read accuracy even through container walls
✓ Unattended operation – scans 100+ containers/minute
✓ Tamper-proof data with encrypted tags
(References: Maersk reported 30% efficiency gains after RFID adoption)
6.2 What RFID frequency is best for shipping container tracking?
UHF RFID (860-960 MHz) is ideal because:
Long read range (up to 15m for moving containers)
Bulk reading capability (entire truckloads at dock doors)
Global compliance with RAIN RFID standards
6.3 Can RFID tags survive harsh shipping conditions?
Seiko’s industrial RFID tags are engineered for:
✔ Extreme temperatures (-40°C to +85°C)
✔ Saltwater/chemical resistance (IP68/IP69K rated)
✔ Impact/vibration proof (MIL-STD-810G tested)
6.4 How does RFID prevent lost/misdirected containers?
Our system:
① Geo-fences key locations (ports, warehouses)
② Auto-alerts for wrong-route containers
③ Blockchain integration for immutable audit trails
*(Example: Hapag-Lloyd reduced lost containers by 92% with RFID)*
6.5 What’s the ROI of implementing RFID container tracking?
Typical results include:
▸ 40% faster loading/unloading
▸ 60% reduction in manual labor costs
▸ 100% inventory accuracy (DHL case study)
▸ <1 year payback period for most deployments