Design Life-Cycle

Luca Vallesi

SAS 043 A04

Professor Cogdell

6 December 2018

RFID Tag Life Cycle Waste and Emissions Analysis

            Radio frequency identification tags, RFID tags for short, are small, lightweight devices used for tracking. They can track everything ranging from animals, items in factories, items being shipped and even recycling. RFID tags function by sending radio waves to a receiver. Since RFID tags can be placed on inlays, paper smart labels or encapsulated in a plastic or glass material, they can be placed anywhere (3). The components of an RFID tag are an antenna, an RFID chip and a substrate (3). The substrate is where the tag is housed together and is the inlay, paper label, or capsule. The RFID chip is what makes an RFID an RFID. It controls how frequently the radio waves get sent out and it contains the memory for when waves get sent back to the tag (3). The waves themselves get are received and sent through the antenna. The antenna is normally made of copper, aluminum, and silver (3). There are two different RFID tag types to perform different purposes. Ultra-high frequency RFID tags are used for short range, yet a very high quantity of tags can be picked up by the sensor (7). Low frequency tags on the other hand can be picked from a sensor from a large distance away, however that reader is only focusing on that tag (7). RFID tags help our world run efficiently. The speed at which they can track and manage items allows companies to output more of their product. Pets and criminals are found faster reducing time spent on tasks that could theoretically never be completed. Through careful analysis of the waste and emissions caused by the material extraction and production of RFID tags, it can be observed that the negative environmental impacts are miniscule compared to the positive socioeconomic impact these tiny devices have on our society.

            Multiple materials are extracted for RFID tags and create waste, but due to the small amount of materials required for production, the environmental impact is quite small. Silicon is required in order to make the RFID chip. The factory production of silicon keeps waste at a minimum. Byproducts such as silica fume, a fine grain silica, and slag are sold by manufacturers to other companies who use this material (9). The production of silicon uses electric arc furnaces which emit small amounts of particulates into the air (9). The RFID chip has anisotropic conductive paste (ACP) on it which allows for electrical currents to run through the chip. The ACP in the chip is made up of nickel. A large amount of waste is produced through nickel processing and extraction. This is due to the ores being smelted only containing 1 to 3 percent nickel (3). Other usable metals are present in the ore, yet a majority is unusable material which can only be dumped. However, this waste is nontoxic as it is only rock and unusable organic material. Next, copper is required for the antenna. Copper creates large amounts of byproducts. Byproducts such as sulfuric acid, gold, silver, and other precious metals are recovered and sold for profit (2). Other byproducts such as overburden from mining, tailings from concentration, and slag from smelting are all waste (2). This waste is particularly dangerous due to the large amounts of dangerous chemicals such as lead and arsenic (2). These chemicals pose a serious threat to the surrounding area they are released in (2). To keep the RFID chip and antenna together, an adhesive is required. The adhesive is made of polyurethane. Very little waste is produced during polyurethane production. Since polyurethane is a manmade material, production can be controlled to only purchase the correct amount of starter materials to prevent excess. To form the polyurethane, polyol and diisocyanate are mixed in a tank and then are sent to a heat exchange (5). The heat exchange is electric which minimizes greenhouse gas emissions (5). The heat exchange causes the chemicals to react to form the state that is required, in this case, an adhesive (5). This produces no waste except for water vapor and any extra starter materials which did not react to form the adhesive (5). Next, n-butyl acrylate is required to connect the chip and antenna to the substrate. N-butyl acrylate is similar to polyurethane as they both produce little waste. One byproduct of the production of acrylate is water (8). Acrylate production is very efficient converting 96.3 percent of all acrylic acid put into the production and 100 percent of n-butanol (8). The leftover 3.7 percent of acrylic acid is reused in another batch of n-butyl acrylate (8). The substrate is made of polyethylene terephthalate (PET). This also has very little byproducts. The main byproduct of PET manufacturing is water (4). The production of PET uses vacuums and pressure instead of heat (4). This removes any gaseous byproduct that could be caused by heating up the chemicals. The only other byproduct would be excess monoethylene glycol, terephthalic acid, and dimethyl terephthalate; the three starter materials (4). Overall the waste of extraction and manufacture of materials required for RFID tag production is low. This is in large part due to the low amount of materials required to build an RFID tag. A large majority of these materials make little to no waste and of those that do, only a few of the byproducts can be classified as waste. After these materials are extracted and processed, they are sent to RFID tag factories and the manufacture of the tags begins.

            The production process of the RFID tag creates almost no waste yet uses large amounts of electricity which can result in high emissions. The transportation of the materials to the factory releases different amounts of waste based on multiple factors. If the source of the materials is further away from the RFID factory, then a larger amount of greenhouse gases will be released into the atmosphere. The type of transport can also affect the amount of gas emitted into the atmosphere. Boats and planes will output significantly more greenhouse gases than trains or trucks. The first part of the production process of RFID tags is making the chip. This requires the silicon and the nickel. This creates a moderate amount of waste because the silicon must be cut in order to make the individual chips (3). This process uses large amounts of electricity and depending on what source of electrical generation is being used, large amounts of greenhouse gases is released. After the chips are cut out, the nickel ACP is put onto the silicon. This creates miniscule amounts of waste as only the required amount of nickel is heated up for it to be malleable enough to be put onto the chips (3). The heating of the nickel uses electricity as well and the emissions produced depends on what form of electrical generation is closest to the factory. Next, the raw copper needs to be shaped into the antenna. If the copper is delivered in a sheet, electricity is only required to power a laser cutter (1). If it comes in other forms the copper needs to be heated, pressed, and then it can go to the laser cutter (1). Depending on which kind of material the factory decides to use, they could use a lot more electricity which resulted in more emissions. No physical waste is produced from this process as the copper that doesn’t become the actual antenna after the punch press can be reused for other antennas or can be sold to other manufacturers. Next, the antenna and chip are put together with polyurethane. The polyurethane is put on using accurate robots which minimizes the use of the adhesive, getting rid of physical waste (1). However, this consumes a large amount of electricity. The emissions depend on where the factory is located and what electrical generation is providing the factory with energy. Next, the substrate needs to be prepared. The PET arrives in chips. It needs to be melted down in order to be made into substrate (1). The liquid is then pushed through a roller that makes the material very thin when it dries (1). After, a laser cutter is used to cut out the substrate. There is no physical waste from this process as the leftover PET can be melted down again and reused. An electric furnace is used to melt down the PET. This is then piped onto the substrate by robots which then place the chip and antenna assembly onto the substrate (1). The emissions are once again determined on what form of electrical generation the factory uses. After this, the RFID tag is finished. The emissions from transportation depends on how far the product is travelling. If the buyer is halfway around the world then the emissions are going to be far higher than if the tag is being shipped within country. When being used, RFID tags typically can’t be maintained; however, they are recycled with great efficiency.

            RFID tags have high recyclability as well as easy waste management after their use resulting in minimal harmful impacts to the environment. During RFID tag use, if an RFID tag breaks, the entire tag will get replaced because it is much easier to do so than to replace one small part of the tag. The tag’s period of use is short since when the item being tracked gets to its destination then the tag is thrown out. The reusability of RFID tags is low because most RFID tags are placed on items for shipping in the paper label and these go into the recycle once people receive the package (7). However, tags that go into or on living organisms can typically be reused once it comes off or if it is taken out (7). Many of the materials inside of the RFID tags can be recycled. The only materials that aren’t recycled are the adhesives from the chip (7). However, the nickel on the chip, the silicon of the chip, the copper from the antenna and the substrate can all be reused (7). In order to do this, the tag is broken down into the chip, the antenna, and the substrate (7). The copper from the antenna is melted down and sent to other factories for copper wiring, copper sheets or even to become RFID antennae once more (7). The substrate is also simple to recycle as it can also be melted down to give back the base material of PET (7). Just like the copper, it can be sold to other companies who want PET, or it can be reused for more substrate (7). The nickel is the most difficult material to recycle as it is melted onto the silicon. In order to get the nickel, the whole chip is melted down and then the melted nickel is separated from the silicon due to its different densities (7). After separation the nickel is cooled and sent to factories. The silicon is also cooled and sent to factories after it is melted. For all these materials, a large amount of RFID tags needs to be processed in order to get a profitable amount of materials due to the low amount of materials inside if RFID tags (7). This is especially true for the nickel. The adhesives are waste from the melting of the components (7). However, because there are extremely small amounts of adhesive it results in minimal waste. Waste management for RFID tags is very easy. Since almost all the materials inside RFID tags can be recycled, RFID tags can be disposed of in the recycle bin (7). This allows for a large amount of the original materials put into making the RFID tag not going to waste and being reused, resulting in low waste and emissions.

            RFID tag’s impact in our world is impressive considering the low waste and emissions they produce that lead to minimal environmental damage. Most of the emissions that result from RFID tag production is due to the large amount of electricity that is required to manufacture them. The overall material usage is quite low which results in the waste caused from extraction to be low as well. Furthermore, since most of the materials can be recycled, this results in very low waste produced over the entire life cycle of the tag.

Work Cited

1.     Baba, Shunji, et al. Radio Frequency Identification (RFID) Tag and Manufacturing Method Thereof

2.     Cavette, Chris. “Copper.” How Products Are Made, www.madehow.com/Volume-4/Copper.html

3.      “Construction of RFID Tags - RFID Chip and Antenna.” RFID4U, rfid4u.com/rfid-basics-resources/dig-deep-rfid-tags-construction

4.      “Polyethylene Terephthalate (PET) Production and Manufacturing Process.” Trusted Market Intelligence for the Global Chemical, Energy and Fertilizer Industries, 6 Nov. 2007, www.icis.com/resources/news/2007/11/06/9076427/polyethylene-terephthalate-pet-production-and-manufacturing-process/

5.     “Polyurethane.” How Products Are Made, www.madehow.com/Volume-6/Polyurethane.html

6.     Roberti, Mark. “Ask The Experts Forum.” From What Materials Are RFID Tags Made? - Ask The Experts Forum - RFID Journal, www.rfidjournal.com/blogs/experts/entry?11066

7.     Schindler, Helen Rebecca, et al. "SMART TRASH: Study on RFID tags and the recycling industry." (2012)

8.     Sert, Emine, and Ferhan Atalay. “n-Butyl Acrylate Production by Esterification of Acrylic Acid with n-Butanol Combined with Pervaporation.” Chemical Engineering and Processing: Process Intensification, Elsevier, 30 Apr. 2014, www.sciencedirect.com/science/article/pii/S0255270114000865

9.     “Silicon.” How Products Are Made, www.madehow.com/Volume-6/Silicon.html

10.  Wise, Edmund Merriman, and John Campbell Taylor. “Nickel Processing.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 5 Sept. 2013, www.britannica.com/technology/nickel-processing

Charles Ringham

SAS 043

Professor Cogdell

6 December 2018

Energy Life Cycle of RFID Tags

            Radio Frequency Identification (RFID) is commonly used in the modern world, from real-time tracking to chipping household pets in case they are lost. Ever heard of the Amazon cashier-less store? Those only work because of RFID. RFID consists of two parts, the tag and the reader, which work hand in hand: the reader scans the tag. There are two types of tags: active, which use a microchip to send data back to the reader; and passive, which only can be read. Passive chips a range of only a few feet, but they do not need a power source; they receive their power from the electromagnetic waves from the reader. In some ways passive RFID tags are like barcodes, but they are much more efficient as they do not put out their own signal, they only need to be near a reader. An example of this is walking out the door of a cashier-less store, there are readers on the exit that scan the passive tags in every item the customer has with them, and then their account is automatically billed. The tags on the items do not transmit any data of their own to the readers. Active RFID has a much larger range, reaching into the hundreds of feet, and require a power source. These are commonly used for tracking packages within facilities, as the reader can ping the active tag anywhere in the building and get a location. Overall, RFID is practical and efficient, and does not use much energy, at least for the device itself. There is quite a lot of embodied energy within RFID tags, which means there is a lot of energy put into the manufacturing process. Although active and passive RFID tags are extremely useful in tracking, manufacturing, and sensing all different types of data, it requires a large amount of energy to produce both types of RFID tags, including creating the microchips in both, the batteries for active tags, and the transportation to the consumer.

            Both passive and active RFID systems require microchips (integrated circuits) in order to function, which has an extensive manufacturing process which requires a lot of energy. The critical metal needed to produce microchips is silicon, which luckily is one of the most common elements on earth. However, it still must be mined, which requires a lot of energy, and the source is being depleted at a very rapid rate (Steadman). The manufacturing process requires an excessive amount of energy per microchip, spread across hundreds of steps. The most important parts of the manufacturing process are the purification of silicon, maintaining the proper conditions inside the building, and the creation of the final chip. For modern microchips to be manufactured, the silicon used must be almost one hundred percent pure because of the very small size of transistors. In 2018, the common number of transistors on a one-centimeter square microchip is around two billion. If there are any impurities on the silicon, such as a dust particle or too high surface roughness, the entire chip will electrically fail. To make this extremely low-entropy silicon, it must be heated to two thousand five hundred degrees Fahrenheit in a furnace that has been purged with argon gas, so there is no air. This heating process requires massive amounts of energy to complete, which only increases as the necessity for higher purity silicon continues to grow. Next, there is the energy used for the actual wafer production after the silicon is in its purest form and it can be worked with in the proper conditions. The energy used in this production phase is thirty to forty percent of the entire energy used in a manufacturing plant. Once the silicon is pure, it is cut into wafers two thirds of a millimeter thick. After they are cut, they go through multiple buffing processes to reduce the surface roughness to less than a millionth of a millimeter. Now the circuit designs which have been designed using computer aided design software can be etched onto the wafers using a photolithographic process, usually consisting of about forty layers (cplai, YouTube). The silicon wafers are coated in a chemical that responds to light, which require more energy to create and purify. This process requires a lot of energy, especially because of the mass quantity of microchips that are being produced, for many different purposes. RFID tags use microchips, but almost every electronic device does as well. Finally, fifty percent of the overall energy that goes into producing a microchip is used to keep the proper conditions in the building. The air in the buildings is restricted to no more than one hundred parts per cubic meter, because there can be no particles that touch the silicon chips or circuit designs anywhere in the manufacturing stage. This energy used to maintain these conditions is split between ventilation and air conditioning (Williams). In total, the electricity used to produce a single centimeter square chip is one and half kilowatt hours. To produce an entire wafer, the figure is close to two thousand kilowatt hours (Decker). Most of this energy is still produced by burning fossil fuels, which is very harmful to the environment and unsustainable. However, the production process of RFID tags is not near complete, as active tags still require batteries.

            As opposed to passive RFID tags, which only get their energy from the reader, active RFID tags require batteries to support their much greater range and features. Though in recent years batteries have gotten more efficient, the process of manufacturing them requires a lot of energy. Most of this energy comes from mining lithium, the key component in modern lithium-ion batteries. These types of batteries are used across a wide variety of products, including smart phones to electric automobiles. Raw lithium can be extracted from brines, or salt rich waters that are pumped to the surface, and the water evaporates over a few months. Many salts are left over, lithium being one of the later ones. The process of pumping the salt rich waters to the surface requires a lot of energy, which is done all around the world, with the most in Australia and South America (Foehringer). Once raw lithium is mined, it must be processed into lithium carbonate for use in batteries and other products, but this requires more energy for transportation. To create a battery, other rare metals such as cobalt, nickel, and graphite are necessary, which take a lot more energy to extract, especially as sources are depleted and deeper mines must be created. Then, all these materials must be put together to manufacture a lithium-ion cell, and many cells go into a completed battery, depending on the size. These are produced in large factories, as they have all sorts of applications, and these factories require large amount of electricity to run. They do not need to be kept as clean as microchip manufacturing facilities, however the machinery requires a lot of power to run. Again, this process applies to many different products, but active RFID tags require these batteries and must take part in the large energy consuming manufacturing industry. Once the microchips and batteries have been produced, the RFID tags can be assembled. This is again done inside factories, increasing the total amount of energy and electricity put into them. Regarding electricity, most electricity used in every process listed so far is mostly generated from non-renewable sources, such as burning coal or fossil fuels. For these fuels, more energy is spent in the massive industry of extracting oil and coal. Then, burning these fuels only results in around forty percent efficiency, resulting in a huge loss of energy (potential electricity) to heat. For the electricity that comes from renewable sources, such as wind and solar, still requires a lot of energy to produce wind turbines or solar panels. Photovoltaic cells require rare metals to produce and do not have very high efficiencies either, resulting in further increased expended energy not directly used in the manufacturing of RFID tags.

            The last energy intensive step in the process of creating RFID tags is the transportation of the materials, final products, and energy usage during their life time. A large majority of ground transportation currently consists of gasoline or diesel-powered vehicles. As previously mentioned, these materials must be gathered from underground and require a lot of energy to do so. Crude oil must go through extensive processing procedures in order to become useful in gasoline or diesel engines, requiring more energy. In addition, gasoline engines are also only around thirty percent efficient in converting energy from the fuel into motion, where the rest is lost to heat. Many products are also transported over long distances by airplanes, which add to the consumption and burning of fossil fuels. After the final products have reached their destination, they still require some energy to operate, through most of the energy usage is embedded. The batteries in active tags must be charged, but that is barely comparable to the energy used in the rest of the process. The readers of both active and passive tags also do not require much energy, only an outlet is necessary. However, electricity delivered to outlets also still mostly comes from burning fossil fuels.

            Overall, low efficiencies in a lot of the manufacturing processes causes the total input energy to produce an RFID tag to increase dramatically. Each of the three main components, microchip and battery manufacturing, as well as transportation, require very large amounts of energy for both gathering materials and running the factories. Because of the battery life, active RFID tags have a lifespan of about three to five years (Smiley). They are too small to repair or recharge the battery, so they are often replaced. This is about the same amount of time that a computer chip will go obsolete, which means the process must continue to make a new chip, further increasing the energy usage. On the other hand, passive RFID chips do not have batteries, so their lifetime is undefined, and theoretically infinite, and require no further energy to operate, except from the reader. To conclude, on the surface it looks like RFID tags are extremely low energy because of their size, and how little power they require to operate, but the embedded energy goes beyond what most people even think to consider. Not only do the manufacturing processes of microprocessors and batteries require a lot of electricity to complete, that electricity mostly comes from the collecting and burning of fossil fuels, or from the production of renewable sources, which also require a lot of energy to produce.

Bibliography

Argyrou, Marinos, et al. Understanding Energy Consumption of UHF RFID Readers for Mobile Phone Sensing Applications. University of Edinburgh, homepages.inf.ed.ac.uk/mmarina/papers/wintech12.pdf.

Bonsor, Kevin, and Wesley Fenlon. “How RFID Works.” HowStuffWorks, 5 Nov. 2007, electronics.howstuffworks.com/gadgets/high-tech-gadgets/rfid.htm.

cplai. “How Do They Make Silicon Wafers and Computer Chips?” YouTube, YouTube, 5 Mar. 2008, www.youtube.com/watch?v=aWVywhzuHnQ.

Decker, Kris. “The Monster Footprint of Digital Technology.” LOW-TECH MAGAZINE, 16 June 2009, www.lowtechmagazine.com/2009/06/embodied-energy-of-digital-technology.html.

Foehringer, Emma. “Lithium-Ion Battery Production Is Surging, but at What Cost?” Greentech Media, Greentech Media, 20 Sept. 2017, www.greentechmedia.com/articles/read/lithium-ion-battery-production-is-surging-but-at-what-cost#gs.RQKHzYA.

Handy, Jim. “Why Are Computer Chips So Expensive?” Forbes, Forbes Magazine, 30 Apr. 2014, www.forbes.com/sites/jimhandy/2014/04/30/why-are-chips-so-expensive/#3b47227279c9.

Nilsson, Björn & Bengtsson, Lars & Wiberg, P.-A & Svensson, Bertil. (2007). Protocols for Active RFID - The Energy Consumption Aspect. 41 - 48. 10.1109/SIES.2007.4297315.

RFID, Star. “Star RFID Manufacturing Process.” YouTube, YouTube, 2 Apr. 2014, www.youtube.com/watch?v=BJeZZS9-xHY.

Smiley, Suzanne. “RF Physics: How Does Energy Flow in an RFID System?” RFID Insider, 30 Mar. 2018, blog.atlasrfidstore.com/rf-physics.

Steadman, Ian. “China Warns That Its Rare Earth Minerals Are Running Out.” WIRED, WIRED UK, 4 Oct. 2017, www.wired.co.uk/article/china-rare-earth-minerals-warning.

Unknown. “Computer Chip Life Cycle.” The Environmental Literacy Council, enviroliteracy.org/environment-society/life-cycle-analysis/computer-chip-life-cycle/.

Unknown. “Construction of RFID Tags - RFID Chip and Antenna.” RFID4U, 2018, rfid4u.com/rfid-basics-resources/dig-deep-rfid-tags-construction/.

Unknown. “Semiconductor Manufacturing: How a Chip Is Made.” Manufacturing | How a Chip Is Made, www.ti.com/corp/docs/manufacturing/howchipmade.shtml.

Williams, Eric D, et al. The 1.7 Kilogram Microchip: Energy and Material Use in the Production of Semiconductor Devices. United Nations University, www.ece.jhu.edu/~andreou/495/Bibliography/Processing/EnergyCosts/EnergyAndMaterialsUseInMicrochips_EST.pdf.

Xinqing, Yan, and Liu Xuemei. “Evaluating the Energy Consumption of RFID Tag Collision Resolution Protocols.” IEEE Xplore, IEEE, 2010, ieeexplore.ieee.org/document/5714503.

Nicolas Rivera

Professor Cogdell

SAS 43

6 December 2018

RFID Tag Raw Materials Life Cycle

            Whether it be tracking a lost dog, monitoring certain health data for medical purposes, or even just keeping track of the products we purchase on a day to day basis, RFID technology plays a major behind the scenes role in the everyday life of the public. Named after its main function, Radio Frequency Identification tags are responsible for the fast scan checkout that many are accustomed to today through the use of radio waves, which are sent to an outside receiver. Once the receiver, or interrogator as it is also known, receives the radio waves from the RFID tag, the data is then collected and then processed before being transmitted back to the transponder. These tags come in a variety of sizes, designed and tailor made for the specific needs of a consumer, factory, or even patient. Though sometimes smaller than a grain of rice and seemingly sustainable due to its deceivingly simple look, careful analysis demonstrates that more raw materials go into this product than many would expect.  

            The main component, some might say the brain, of an RFID tag is the chip itself, which gives the first insight into just how many materials go into this product beginning with the utilization of silicon. Though there are two different types of RFID tags, passive tags and active tags, both utilize the arguably most important of any tag, the chip. Seemingly small and ordinary, production of these chips goes further than many would even think, starting with a grain of sand. Fabrication plants specifically designed for making microchips begin the process of creating silicon by first melting and refining sand until it becomes 99.99% pure, single crystal silicon ingots. Once finished making the journey from sand to ingot, said ingots are then sliced by saws into dime thick wafers, which span several inches in diameter and are then cleaned and polished before each one is utilized to build multiple chips. Special attention is given to the environment in which these steps are taken to prevent contamination and destruction by foreign substances or even dust. After the wafers are cut, they are then covered with a layer of silicon dioxide, which has been known to cause silicosis of the lungs if inhaled too much or safety precautions are not properly taken. On top of this layer of silicon dioxide is then added another layer of photoresist, a photosensitive chemical that hardens when exposed to light, leaving the unexposed areas to be etched out to different depths. This etching creates a 3D landscape on the chip that is reminiscent of a circuit design and is then overlaid with aluminum to create conducting paths. As seen in the complex process of making the chip alone, several materials are already utilized in the beginning of an object that still holds several components.

            Of the components still not discussed, the next most important one after the chip is the antenna of the RFID tag, which doesn’t just utilize one type of metal, but several. The antenna of an RFID tag can be made of silver, copper, or aluminum ink or even something else as long as its conductive. Being the largest part of the RFID tag, the antenna alone uses a significant amount of metal that has to be extracted from the earth in a lengthy, costly, and environmentally detrimental process. The antenna is the actual part of the RFID tag that receives signals sent by the interrogator and may either transmit another signal back in an active tag or reflect the signal back if it’s a passive tag. In addition, the antenna in passive tags also gains its power from the radio waves being transmitted and then supplies back to the tag’s chip. Not only can the antenna be the power supplier in some cases, it can also allow the tag to have different behaviors or properties based on the antenna design itself. For example, several antenna shapes are spiral, single or dual dipole, or folded dipole. Though the antenna may be designed for a specific frequency and design, this also means that the materials used in the tag are heavily dependent on the antenna design, seeing as how it’s the largest component of an RFID tag. The aluminum, copper, and/or silver are deposited on to the tag at very high speeds using one of several methods often employed. These three process are the copper etching method, which creates a highly efficient antenna but is not very cost effective, the foil stamping method, which is also known for being highly efficient but not cost effective, and lastly, the screen printing method which is the fastest and cheapest method of the three but creates antennas that have proven to not be very efficient. Although the antenna and the chip are the livelihood of the RFID tag, they have to be put on something to hold them together and keep them from separating.

            The substrate is what holds the RFID tag together and is responsible for keeping all its components in one place, and is sometimes aided, in the case of implantable chips, by an encapsulation. The chip and antenna are mounted on the substrate, which is usually made of paper due to its flexible nature or plastics like PET or polyethylene terephthalate depending on what the RFID tag is being used for. The antenna is physically printed onto the substrate and then the chip is attached to the antenna and the substrate. Flexible substrates like paper are most popular for passive tags as long as the thickness of said substrate does not exceed 200mm so it can still read the radio waves being transmitted by the interrogator. However, thickness is only a minimal factor when it comes to picking the right substrate for the RFID tag, in fact, this tag, depending on its purpose, has to be able to withstand a wide range of conditions that it may encounter or have to go through during its life cycle. For this reason, other sturdier substrates utilize materials such as polymer, PET, phenolics, PVC, or even styrene. Some of the check points when it comes to picking the right substrate for an RFID tag are its ability to stop static build up, how smooth it is for printing the antenna onto it, durability, and overall protection for the antenna and the chip. The substrate may also be vulnerable to heat, vibration, chemicals, corrosion, impact, and even sunlight. For this reason, implantable tags like the ones used to monitor pets or health data in humans have to be encapsulated in hard plastic like PET or glass. This is because these RFID tags will be subjected to harsh environments like high body temperatures and possible changes in acidity.

            As demonstrated through a thorough analysis and in-depth investigation into the raw materials utilized in the production of RFID tags, it can be reasonably stated without a doubt that these tags use and may possibly waste a very large amount of resources that many are oblivious too. Although a crucial and albeit far more convenient addition to the lives of many, from a sustainability standpoint, RFID tags may not make the cut when it comes to resource usage and should be redesigned to fit a greener future.

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