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RFID – Radio Frequency Identification

The use of RFID in the warehouse and food supply line logistics have long been debated, when compared to its predecessor the barcode, its efficiency is unmatched. The cost however was significantly more, with almost every technology as it developed the price decreases and therefore becomes viable. Michael (2005, P.6) Supports this by stating ‘The technology promises to transform the way organizations currently forecast demand, manage inventory and distribution, and market to consumers within the store’. Not requiring user input or line of sight, RFID provides instant data entry explained by smith et al (2018) that further expand on the many qualities of RFID such as being able to communicate large volumes of data both simultaneously and in milliseconds. RFID also reduces labour as it replaces the previous labour requirements created by barcodes, examined by Bagchi (2007).

Sharma et al (2013) compares RFID to barcodes, explaining how it can improve data collection not only because line of sight is not required but because RFID tags can be read at a rate of several hundred reads per second over several meters. Specifically, requiring no line of sight is a huge advantage in data collection as this removes the chance for human error. This is incredibly important in inventory management because human error is costly and has the potential for serious harm to health, in some cases it can be lethal. 

Key characteristics required for RFID inventory management systems is a read range greater than the distance of a doorway (portal) and the ability to read labels within any given orientation. To achieve adequate read lengths in inventory management, the polarization of the antennas needs to be understood. Polarization of the RFID antennas typically occur as either linear polarization and circular polarization, Fink et al (2018) and Taskhiri et al (2018) both discuss the use of each polarization including the benefits and the drawbacks, including but not limited to those given in table 1.

Linear Polarization Circular Polarization
Longer Read Range. Shorter Read Range.
Tags and read need to be on the same plane and have similar height. Tags and the reader can be on different planes at different heights.
The reader needs to know the orientation of the tag. The reader does not need to know the orientation of the tag. Better for applications where you cannot predict tag orientation.

Table 1: Linear and Circular Polarization (everythingrf.com, 2018)

A linear polarization occurs when the radio waves are broadcast on a single plane, either vertically or horizontally. A circular polarization occurs when radio waves are broadcast on a plane that rotates at a constant rate perpendicular to the direction of the waves shown in figure 1. Because of this circular polarization gives a higher read probability, therefore is more suitable to inventory management in particular where products shape, size and orientation vary. This type of polarization will be a fundamental requirement of the RFID antenna equipment used in Anthropoids inventory management systems.

Figure 1: Linear and Circular Polarization (everythingrf.com, 2018)

In both systems explored by LI et al (2017) and Bunker et al (2017) the RFID system is composed of four components, RFID labels, antennas, readers, and a central computer system where a database and management software is stored. The RFID label contains a unique serial number which makes it the data carrier. The antenna is responsible for generating radio singles that activate the tag so that the reader can translate the returning signal into the corresponding unique serial number, this is then communicated to the central computer system for further use. 

Although RFID was used in World War Two to identify planes that were allies, it was in 1948 when the scientist and inventor Harry stockman was credited for the invention. Sharma et al (2013) explains that the technology was patented in 1973 and only became cost effective during recent years due to its increased development, crossing the threshold of return on investment making it viable for commercial use. 

The food supply chain often ends at supermarkets and stores alike, Siawsolit et al (2018) discusses the use of RFID in these environments to convert unsatisfied demands into alternative online sales strategies. These studies have suggested an average profit enhancement of 69.6% through converting waste into sales. Soler et al (2019) further explains that producing a large number of perishable products often results in a waste of perishables due to negligence or shelf life, this also results in an increase in the inventory holding cost. Also supported by Artigues et al (2013) and Costa et al (2013) that state problems consist of generating schedules of both minimal interruption, duration, and traceability. More on this can be read in our blog about inventory management and algorithms for inventory management. 

ARTIGUES, C., DEMASSEY, S. and NERON, E. 2013. Resource-constrained project scheduling: models, algorithms, extensions and applications. John Wiley & Sons.

BAGCHI, U., GUIFFRIDA, A., O’NEILL, L., ZENG, A. and HAYYA, J., 2007. The effect of RFID on inventory management and control. In TRends in supply chain design and management (pp. 71-92). London: Springer.

BUNKER, R. and ELSHERBENI, A., 2017. A modular integrated RFID system for inventory control applications. Electronics. 6(1), p.9.

EVERYTHINGRF, 2018. Circular polarization vs linear polarization for rfid applications [online]. Available from: https://www.everythingrf.com/community/circular-polarization-vs-linear-polarization-for-rfid-applications [Accessed 12 January 2020]

FINK, P., LIN, G., NGO, P., KENNEDY, T., RODRIGUEZ, D., CHU, A., BROYAN, J. and SCHMALHOLZ, D., 2018. RFID Reader Antenna with Multi-Linear Polarization Diversity.

LI, L., ZHAO, Y., OLIVEIRA, J., VERHOIJSEN, W., LIU, K. and XIN, H., 2017. A UHF RFID system for studying individual feeding and nesting behaviors of group-housed laying hens. Transactions of the ASABE, 60(4), pp.1337-1347.

SHARMA, A. and THOMAS, D., 2013. Looking backwards to look ahead: Lessons from barcode adoption for rfid adoption and implementation. In Proceedings of the Conference for Information Systems Applied Research ISSN (Vol. 2167, p. 1508).

SIAWSOLIT, C., GAUKLER, G. and SEEPUN, S., 2018. January. RFID-Enabled Management of Highly-Perishable Inventory: A Markov Decision Process Approach for Grocery Retailers. In Proceedings of the 51st Hawaii International Conference on System Sciences.

SMITH, S., OBERHOLZER, A., LAND, K., KORVINK, J.G. and MAGER, D., 2018. Functional screen printed radio frequency identification tags on flexible substrates, facilitating low-cost and integrated point-of-care diagnostics. Flexible and Printed Electronics. 3(2), p.025002.

TASKHIRI, M.M., SOLEIMANI, M. and HASHEMI, S.M., 2018. Multibit RFID tag with wideband circular polarization antenna. Microwave and Optical Technology Letters. 60(5), pp.1304-1309.

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