'Near Field UHF'에 해당되는 글 7건

  1. 2008.02.28 Wal-Mart Seeks UHF for Item-Level
  2. 2008.02.28 RFID Vendors Unite Behind Item-Level UHF
  3. 2008.02.28 Near Field UHF Versus HF
  4. 2008.02.28 A Shift to UHF Near-Field Predicted for Pharma
  5. 2008.02.26 Near Field UHF - Manufacture
  6. 2008.02.26 Near Field UHF - Pharma
  7. 2008.02.25 Near Field UHF 기술 - Item level tagging
2008. 2. 28. 18:01

Wal-Mart Seeks UHF for Item-Level

During a recent webinar, the retailer's RFID solutions architect explained his company's criteria for successful item-level tagging.

By Mary Catherine O'Connor

Mar. 30, 2006—Speaking yesterday to an audience attending RFID Journal's webinar entitled "Item-Level Tagging Using UHF Gen 2, Richard Ulrich, solutions architect on Wal-Mart Stores's RFID strategy team, laid out a number of requirements his company has identified as being crucial to the success of item-level tagging. There is a need for low-cost tags and infrastructure that benefit from economies of scale, he said, and a tag used to identify goods at the item level must have a narrow read range to ensure that interrogators built into point-of-sale terminals read only those tags on items being purchased. At the same time, tags on stacked items must be readable so goods sitting on shelves can be read simultaneously.

In addition, since television sets and other large consumer items are packed and sold in single-item cases, they must be read from a distance as they move through portal readers while in transport, and again at short range at the point of sale. Any tag used at the item level must also follow a globally accepted protocol, since goods move between many countries and regulatory environments.

Before defining a strategy around item-level tagging, however, Ulrich said the industry must develop a common approach not only to what technology standards it will use, but also to how it will categorize the goods to be tracked at the item level. For example, he asked, "if Wal-Mart considers aspirin a fast-moving consumer good, and CVS calls it a pharmacy item, how will that impact the manufacturer?" If the pharmaceutical industry decides to use HF tags to identify products, but retailers require only UHF tags at the item level, this could put some manufacturers of goods sold in both retail and pharmacies in a difficult position.

"Gen 2 tags are performing very well at the case and pallet level, but can UHF Gen 2 be used at the item level? If it can, then that's what we need," Ulrich explained. "There are two technology standards for electronic article surveillance, so DVD makers need to use both types of EAS tags. We don't want that same type of thing to happen with RFID."

Chris Diorio, chairman, founder and vice president of RFID engineering at the Seattle-based RFID chipmaker Impinj, and Ian Forster, technical director of RFID for tagmaker Avery Dennison, also spoke during the webinar, which was sponsored by Impinj. Both men expressed their belief that Gen 2 UHF tags can be used at the item level, and presented to webinar attendees the reasons they believe this possible.

The approach is simple, they said: Without altering the Gen 2 chips or the air-interface protocol, manufacturers can use tag and interrogator antennas specifically tuned for near-field operation, which uses the magnetic energy field between the tag and reader antenna to communicate data, thereby shrinking the tag's read range and making the reader's interrogation zone more targeted.

Diorio said the near-field prototype tags and readers Impinj demonstrated last month performed as well as high-frequency tags when placed on items containing water or metal—notorious for causing RF interference with conventional UHF tags designed for far-field transmissions, or those using the electromagnetic energy field. In fact, he added, Impinj has demonstrated a number of its near-field UHF Gen 2 tags being read while submersed in liquid. This is because the near-field tags transmit through the magnetic field, and their transmissions are unaffected by dielectrics—materials that cannot conduct electricity—whereas the RF signals reflected by far-field UHF tags, which use the electromagnetic field, are attenuated by dielectrics.

Many end users, especially those in the pharmaceutical industry, are testing and using HF tags in pilots because they find that HF offers better performance than the UHF tags on the market today.

ODIN Technologies, a systems integrator based in Dulles, Va., released this week the results of a benchmarking test showing that HF tags outperformed UHF tags in both lab tests and use-case scenarios involving pharmaceutical products tagged at the item level (see Study Says HF Rules for Pharma Items). During the webinar, Diorio said the ODIN report was based on a foregone conclusion because ODIN used only commercially available tags and, therefore, compared HF tags with far-field UHF tags, which are not designed to work at close range. Diorio says tags using UHF Gen 2 chips and antennas designed for near-field RF communication—which he said are months away from being commercially available—are very well suited for the item-level tagging of pharmaceutical products.

In fact, said Diorio, near-field UHF tags have an advantage over HF tags when used in the supply chain, where goods need to be interrogated while in motion, because the higher frequency facilitates faster encoding and reading than HF tags do. Moreover, he said, UHF tag antennas can be built more cheaply and quickly than HF antennas since UHF tags can contain an antenna that is a less precisely designed and conductive.

According to Diorio, Impinj has developed a tag antenna design called the Satellite, which has a small loop antenna in the center, linked to a larger antenna surrounding the loop. The Satellite is designed for both far- and near-field reading. When presented to a near-field reader antenna, it transmits in the magnetic field, and when presented to a far-field reader antenna, it functions like a far-field tag, using the electromagnetic field.

Forster says Avery Dennison has been working with Impinj to develop EPC Gen 2 inlays using near-field antennas. Exploiting a UHF tag's near-field capacity is nothing new, he explained—RFID printer-encoders such as those manufactured by Avery Dennison use near-field reader antennas to encode and verify the UHF tags embedded in smart labels. Avery Dennison also uses near-field reader antennas in its tag-testing machinery. According to Avery Dennison senior business development manager Andy Holman, two inlays in the company's recently expanded Gen 2 portfolio (see Avery Dennison Unveils New Gen 2 Inlays) use near-field antenna designs. Specifically, the AD-811 and AD-812 inlays for pharmaceutical applications contain an antenna designed solely for near-field transmissions, while the AD-820 and AD-821 inlays for apparel and other item-level applications contain an antenna designed for both near- and far-field.

If using UHF tags to track goods at the item level requires nothing more than new antenna designs, if none of the air-interface or chip specifications need to change, and if printer-encoders already use near-field to produce smart labels, then why is the concept of a near-field UHF tag for item-level tagging just now coming to the fore?

"Nobody was asking the questions," explained Diorio. "Everyone was too focused on case- and pallet-level tags. But the technology was there—it only took us about four weeks of experimentation to make our first prototype."

From RFID Journal
Trackback 0 Comment 0
2008. 2. 28. 18:00

RFID Vendors Unite Behind Item-Level UHF

The ongoing debate about whether HF or UHF RFID is the superior technology for item-level tagging of pharmaceuticals will see another development tomorrow as a white paper is released that argues strongly for UHF. Sponsored by heavyweights ADT/Tyco Fire & Security, Alien, Impinj, Intel, Symbol, and Xterprise, the paper presents an argument -- supported by empirical evidence compiled by the companies -- that "dispels myths" about UHF RFID and demonstrates why it is in fact the right choice for pharma-tracking. RFID Update spoke about the paper and its purpose with Vinay Gokhale, vice president of RFID business development for Impinj, the company that has emerged as the de facto leader of the item-level UHF camp.

Ever since Impinj announced Gen2 UHF technology for use at the item level just before the RFID World conference in late February, interest in its possibilities has been building, according Gokhale. Consequently, so too has the debate about whether UHF is actually feasible. The long-held view by most in the industry is that UHF cannot be used at the item level -- particularly for pharmaceuticals -- because proximity to metals and liquids causes unacceptable degradation in performance. Impinj's "near-field UHF" item-level solution directly challenges this view, allowing UHF tags to be used in and around metal and liquid. At its booth at RFID World, the company displayed a simple but impactful demonstration to drive the point home: near-field UHF chips were floating in a Gatorade bottle filled with water while still being actively and accurately read by a nearby reader. Flying in the face of conventional industry wisdom, it was one of the most buzz-generating demonstrations on the show floor.

It is precisely this conventional wisdom that Impinj and the other white paper sponsors are now seeking to counter or, at the very least, question. Instead of treating it as a forgone conclusion that UHF can't work at the item level, the informal pro-UHF consortium believes the industry should integrate the recent developments around near-field UHF's capabilities and consider whether the conventional wisdom is flawed. "As an industry we need to have a discussion about this with the more recent [UHF developments] instead of years-old information that people are baking into their analyses," Gokhale commented. It is the sponsors' hope and expectation that this white paper will serve as the starting point. In one cohesive document, the argument for near-field UHF is refined and presented based on the findings from numerous tests conducted by all the sponsoring companies. "What the group has concluded is that UHF Gen2 is the ideal protocol and frequency for item-level pharmaceutical applications," said Gokhale.

In a nutshell, that conclusion rests on the following arguments:
  • Near-field UHF does work on and in close proximity to liquid
  • It also works on metal, and in fact leverages metal's physical characteristics to boost performance
  • The tight read range requirements of item-level applications can be accommodated by UHF
  • UHF can be as secure as HF
  • It provides 500% higher read speeds than HF
  • UHF tags are cheaper to produce than HF tags
  • They can also be smaller and more customizable in shape ("form factor")
The new white paper contradicts the findings of another document released earlier this year by RFID solutions provider ODIN technologies. In the benchmark entitled Pharmaceutical RFID: Battle of the Frequencies, ODIN concluded through its own testing analysis that HF is clearly superior to UHF for item-level tagging in the pharmaceutical supply chain (see Report: HF Wins First Round of RFID Frequency Battle). A key caveat to the findings, however, is that ODIN did not evaluate near-field UHF during the benchmark's production because sample product was not made available in time. Were ODIN to reevaluate using the near-field product available today, Gokhale expects that it "would come up with quite a different conclusion." While ODIN has not announced its intention to do so, the release of a follow-up item-level pharma benchmark seems likely given the developments in near-field UHF.

Aside from the new white paper's findings, the prestige of its sponsorship is also notable. With ADT/Tyco Fire & Security, Alien, Intel, Symbol, and Xterprise backing the document, some of the biggest industry names have effectively thrown their weight behind UHF for pharma. Add to that list Wal-Mart, which has been a vocal proponent of UHF, and Avery Dennison, which lent implicit support to UHF by co-hosting the Item-Level Tagging Using UHF Gen 2 webinar with Impinj in March, and it becomes clear that the UHF camp is shoring up very meaningful support.

Important to note, of course, is that ultimately the buyers' opinion matters most, not that of the RFID vendors. Near-field UHF will not necessarily "win" by adding more vendors to its camp, but by securing the support -- and purchase orders -- of the pharmaceutical manufacturers, wholesalers, and retailers. These firms are probably open to being convinced; they simply want the technology that best addresses their problems of counterfeiting and shrinkage. If Impinj et al. make their argument convincingly, the pharma supply chain stakeholders may just change their thinking. Faster, broader, and more effective adoption of RFID is, after all, what everyone wants.

From RFIDUpdate
원본: http://www.rfidupdate.com/articles/index.php?id=1133
Trackback 1 Comment 0
2008. 2. 28. 17:58

Near Field UHF Versus HF

Near Field UHF Versus HF

Item level tagging is going to be the biggest market for RFID. However, despite many companies wanting everything at one frequency - UHF - the limitations of far field UHF systems with water and metal have hindered this. Recently there have been big developments in near field UHF, with companies citing performance similar to that of HF tags. IDTechEx provides an independent analysis.
May 16, 2006

Item level tagging is going to be the biggest market for RFID. It has special requirements - for example, the tags must be very small and be read in large groups, with no confusion about which is which. Water and metal are frequently in, on or near these items, yet exceptionally high read accuracy is demanded with drugs, jewellery etc. Smart shelves, often made of metal, need to distinguish one from another, however small the items are and there must be robust capability for multi-tag reading.
Wal-Mart mandates UHF for item level drugs: many leading drug companies, all libraries and most laundries fit HF RFID on their items. There is not room for two tags on many of the items. We must not repeat the lunacy of anti-theft tagging where consumer goods suppliers alternately have to fit one of three incompatible tags on each type of item depending on who buys it and there are three incompatible infrastructures out there. Even two incompatible systems for the same items would be problematical and expensive.
To make matters worse, the transition from case to item level is far from distinct. 15% of Wal-Mart's general merchandise is "case pack one-of-one". It is therefore difficult to separate "item" vs "case", if there is to be one type of tag for each.
Best of both worlds?
Recently, many of the UHF proponents have switched to recommending what they see as a "best of both worlds" hybrid called Near Field UHF, although it has limited commercial availability as yet. Technically, this usually means that the standard UHF Gen 2 chip is used in the tag but a different antenna is fitted to tag and interrogator so they work at H Field in so-called near field coupling i.e. like an HF tag.
With a very simple antenna printable at high speed, this will be the cheapest EPC tag. To a large extent, it gives the best of both worlds and it can be combined with conventional long distance E Field UHF by having dual antennas in tag and interrogator - or different interrogators can be used for the two types of UHF label - pallets/ cases vs items, say. Or such is the dream.
If near field UHF lives up to its promise and its limitations are overcome such as high interrogator cost, then its potential cost and other benefits may lead it to being used on a lot of items. However, we shall not have one-tag-fits-all because combined NF/FF UHF tags are too big for many items and UHF tags for pallets, cases, air baggage etc will always need to come in many variations tuned to what they are to sit on. That is a problem with UHF.
Not surprisingly then, no supplier is ceasing its activity in HF RFID and some UHF RFID suppliers are broadening their capability to HF. Hedging of bets may be in order and the likely outcome is that there will be a place for both solutions but rarely on the same product.
Complex matter - winners and losers
The impending stand off between these options in RFID in general is a complex matter and IDTechEx technical experts have taken inputs from many of the most respected designers to create a mini paper Near Field UHF vs HF for Item Level RFID - an Independent Analysis. This has 5000 words, eight figures and a detailed comparison chart and it can be purchased for just $189 / €149 from here. Getting it right is key to the commercial success of the many RFID companies now in this enormous but fast changing market arena.
Dr Richard Fletcher of TagSense will demonstrate NF UHF and Ian Forster, Technical Director RFID of Avery Dennison also clarify the position at the forthcoming IDTechEx conference RFID Smart Labels Europe London September 19-20 www.smartlabelsEurope.com
For further information, also see Item Level RFID.

From IDTechEx

'기술 관심 > RFID' 카테고리의 다른 글

디바이스 미들웨어 1 - RFID 미들웨어를 넓게 보자  (0) 2008.05.09
RFID Middleware is Extinct.  (0) 2008.03.06
Near Field UHF Versus HF  (0) 2008.02.28
Near Field UHF - Manufacture  (0) 2008.02.26
Near Field UHF - Pharma  (0) 2008.02.26
Near Field UHF 기술 - Item level tagging  (0) 2008.02.25
Trackback 0 Comment 0
2008. 2. 28. 17:46

A Shift to UHF Near-Field Predicted for Pharma

Andrew Nathanson, of the market research firm Venture Development Corp., says the pharmaceutical industry will increasingly adopt hybrid HF-UHF RFID solutions over the next five years, followed by near-field UHF technology.

By Claire Swedberg

Oct. 3, 2006—The pharmaceutical industry will migrate toward hybrid HF-
UHF RFID solutions for the medication supply chain in the next five years, then shift to near-field UHF technology, according to Andrew Nathanson, practice director for AIDC and RFID technologies at market research firm Venture Development Corp. Nathanson addressed RFID's future for the pharmaceutical industry at the RFID Journal Industry Summits conference on Wednesday, Sept. 27.

Traditionally, pharmaceutical manufacturers and wholesalers have used HF RFID tags and readers, which do not have the fast
read rate of UHF but which offer greater capacity to read in hostile environments, such as with liquids and metals. They are also more effective at reading multiple items in a small space, such as many bottles stacked in a carton passing through assembly lines at a fairly high speed.

Andrew Nathanson
Near-field UHF technology is capable of transmitting in the near-field, similar to HF, but is faster and works well around metals and liquids. Impinj demonstrated a prototype of its near-field UHF solution eight months ago, offering UHF technology with chips and readers designed especially for item-level tagging applications that perform like HF hardware.

Nathanson predicts that the availability of
EPC Gen 2 near-field UHF hardware will change that scenario, since the technology operates well in liquids and metals and reads more items at a faster rate (about 500 percent faster) than HF. It can encode RFID tags at a rate 75 percent faster than HF, Nathanson said, but the technology has not caught up with science.

"The physics are there, but they have to work out the details," Nathanson explained. Some of those details include integrating the near-field and far-field capabilities, as well as bringing costs down for the technology. UHF interrogators capable of reading both near-field and far-field tags are expected to be 50 percent more expensive than current RFID readers, which are designed to read tags only in the far field. Moreover, the technology will require dual antennas and a dual software package to distinguish between transmissions from the two antennas.

In the meantime, as an increasing number of pharmaceutical companies seek item-level RFID solutions, Nathanson said, there will be a growing number of hybrid solutions. Those hybrids can be combinations of HF and UHF RFID systems, such as UHF for cases and pallets, and HF tags or combinations of HF tags and 2D bar-codes labels at the item level. They can also be combinations of RFID tags with sensors able to measure shock, temperature, humidity and other conditions, to track whether medications travel through the supply chain without damage. These semi-passive RFID tags, Nathanson said, are similar to passive tags in that they depend on the RF signal of an
interrogator to transmit their data. However, they also contain a battery that allows the tag to monitor environmental conditions (see Pharma Label Maker to Test Tags That Record Temps).

According to Nathanson, the use of HF alone for item-level tagging is not a long-term solution for the pharmaceutical industry. UHF's growth is making inroads in HF's popularity, even on the item level.
Wal-Mart, for example, has already required most of its suppliers to affix EPC UHF tags to all cases and pallets of goods the retailers buys. In addition to the support that UHF receives from Wal-Mart, "there are three to five times more dollars being put into UHF research and development than in HF," Nathanson said, adding that pharmaceutical manufacturers still have not accepted UHF.

"We can expect a few years of debate, with the balance shifting toward UHF," Nathanson stated, with more drug manufacturers and wholesalers adopting hybrids until near-field UHF hardware becomes available and affordable. Nathanson maintained that once vendors are able to achieve an effective integration between the dual systems, as well as the
antenna design intended to transmit around metal, such interrogators will become pervasive. This will happen, he predicted, "in about five years."

From RFID Journal

Trackback 0 Comment 0
2008. 2. 26. 13:06

Near Field UHF - Manufacture

이번에 보여지는 동영상은 역시 의약품에 적용한 내용인데 컨베이어 벨트에 태그가 붙은 개별 약품이 총알같이 지나가고 이때 각 태그에 값을 쓰고 읽어 검증해서 문제가 있으면 컨베이어를 세우는 형태로 진행한다. 놀라운 것은 조그만 안테너 범위 내에 들어왔을때만 태그가 인식되고 안테너 뒷면에는 전혀 읽히지 않는다는 것이다.

일반적으로 UHF RFID를 적용할 경우 제조시에 태그를 쓰고 읽기를 하면 속도 문제로 처리하기가 쉽지 않을 뿐 아니라 주변 간섭 때문에 (멀리 있는 태그가 읽히거나 노이즈로 인해 잘 읽히지 않거나) 에러 율이 매우 높아 제조 공정에서는 저주파를 사용하고 UHF 같은 고주파는 사용하기가 거의 불가능했다. 게다가 안테너 뒷면과 옆면에도 전파가 나오기 때문에 원하지 않는 결과가 종종 발생하기도 한다.

이런 문제를 Near Field 방식을 적용했을 때 해결할 수 있다는 내용을 담고 있다.

'기술 관심 > RFID' 카테고리의 다른 글

디바이스 미들웨어 1 - RFID 미들웨어를 넓게 보자  (0) 2008.05.09
RFID Middleware is Extinct.  (0) 2008.03.06
Near Field UHF Versus HF  (0) 2008.02.28
Near Field UHF - Manufacture  (0) 2008.02.26
Near Field UHF - Pharma  (0) 2008.02.26
Near Field UHF 기술 - Item level tagging  (0) 2008.02.25
Trackback 0 Comment 0
2008. 2. 26. 12:56

Near Field UHF - Pharma

계속해서 ImpinJ 라는 회사의 선전(?)을 좀 해야겠다. 여기에서 보여 줄것은 ImpinJ 라는 회사의 기술력을 보여주고자 함이 아니라 Near Field UHF 방식을 사용함으로 해서, RFID 기술을 모든 물건에 붙여서 계산대를 통과할때 한꺼번에 읽겠다는 당찬 포부가 그동안 불가능했다라는 사실을 극복할 수 있다라는 가능성을 보여 준것이기 때문이다.

참고로 ImpinJ는 원래 UHF RFID 의 태그 chip을 만드는 회사다. Gen2 라는 표준을 만들어 두고 제대로 시장이 활성화 되지 않는 UHF RFID 시장의 문제점을 직접 해결하고자 하는 노력으로 Reader도 만들고 이런 노력도 하지 않나 생각한다. 목마른 사슴이 우물을 파는 법이지...

어찌됐건 이 회사는 자사의 리더만 만들어 팔아 먹는게 아니라 설계를 OEM 방식으로 팔아서 다른 회사에서도 ImpinJ 와 같은 리더 기술을 사용할 수 있다는 것이다. 우리나라의 경우도 LS 산전이 이러한 방식으로 리더를 생산한다.

다음 동영상은 의약품에 Near Field UHF 태그를 부착한 모습이다. 수백병의 조그만 약병에 태그를 안테너와 수직된 방향으로 부착해서도 인식되는 정확도와 속도가 놀라울 뿐이다. 이러한 성능은 본인이 직접 눈으로도 확인한 바 있다.

본인이 생각할 때 Near Field UHF의 장점은 다음과 같다.

- 일반적으로 저주파의 경우는 인식 속도도 느리고 한꺼번에 여러개 읽는 게 한계가 있다. 반면에 물이나 금속 등 주변 환경에 둔감한 장점이 있는데 Near Field UHF는 모든 장점을 취할 수 있다. 빠르고 여러개의 태그를 환경에 둔감하게 인식할 수 있는 것이다. 인식 거리가 짧아지는 단점이 있는데 Item level Tagging은 오히려 짧은 거리가 더 요구된다.

- 13.56 MHz 태그 제조 방식에 비해 싸고 작게 만들 수 있다. 13.56 MHz 방식의 태그는 여러 겹의 안테너 코일을 감아야 한다. 이는 제조 공법 상 비용이 많이 들 수 밖에 없고 크기를 작게 만들기도 어렵다. 하지만 UHF 의 경우는 하나의 루프만 형성되어도 Inductive coupling을 쓸 수 있다.

- Near Field UHF는 리더 안테너와 태그 안테너 만 바꾸면 되므로 기존의 인프라를 그대로 이용할 수 있으며 필요하면 태그 안테너를 Far Field 와 Near Field 동시에 쓸 수 있도록 태그 패턴을 만들면 두가지 방식을 선택적으로 사용할 수도 있다.

외국의 경우는 몇년 전부터 독일의 Metro, 미국의 BestBuy, Wal-Mart 등도 이러한 방식을 적용하고 있다. 국내의 경우도 이제 이 기술에 눈을 돌려 올해 정부 기술 개발 내용에 포함 시키고 있다.

'기술 관심 > RFID' 카테고리의 다른 글

디바이스 미들웨어 1 - RFID 미들웨어를 넓게 보자  (0) 2008.05.09
RFID Middleware is Extinct.  (0) 2008.03.06
Near Field UHF Versus HF  (0) 2008.02.28
Near Field UHF - Manufacture  (0) 2008.02.26
Near Field UHF - Pharma  (0) 2008.02.26
Near Field UHF 기술 - Item level tagging  (0) 2008.02.25
Trackback 0 Comment 0
2008. 2. 25. 18:23

Near Field UHF 기술 - Item level tagging

본인은 RFID 업체 중에서 ImpinJ (http://www.impinj.com) 라는 회사를 개인적으로 좋아한다. 뭐 이 회사와 개인적으로 친하게 만나 본 적이 있거나 여기에서 뭘 얻어 먹은 적은 없지만, 다른 사람들과 다른 생각을 하고 뭔가 눈에 보이는 뭔가를 해 내고 있는것 같기 때문이다.

그 중에 본인 개인적인 생각에 RFID 역사에서 가장 큰 획을 그은 것으로 판단되는 것이 바로 UHF 를 Near Field 방식을 사용하자는 아이디어 이다. 일반적으로 UHF 같은 고주파에서는 Far Field 방식을 사용하는데 저주파에서나 사용하던 Near Field 방식을 쓰자는 것이다.

다음은 그들이 이야기 하는 UHF RFID의 오해 7가지 이다.

       UHF Gen2 태그는 Item Level로 사용하기에는 너무 크다

해답: 일반적으로 UHF 는 장거리를 요구하고 이에 따라 안테너 크기가 커야만 한다. 하지만 near-field로 사용하면 매우 작은 크기만으로도 충분하다.


       13.56 MHz 가 진정한 국제 표준이다

해답: 현재로서 UHF Gen2 EPCglobal 뿐 아니라 ISO 18000-6C 로 국제 표준을 만족한다


       UHF Gen2는 액체에서 동작하지 않는다

해답: UHF far-field는 액체에 영향을 받는다. 하지만 near-field의 경우는 그렇지 않는다. 심지어는 물속에서도 동작을 한다.


       UHF Gen2는 금속에서 동작하지 않는다

해답: 모든 주파수와 near-field, far-field 방식 모두 금속에 영향을 받는다. 하지만 금속 성질을 이용하여 여러 종류의 금속 태그 솔루션들이 나와 있는 상태이다.


       UHF Gen2는 서로 매우 가까운 거리에 있으면 동작하지 않는다

해답: UHF near-field 로 제작되면 HF에 비해서 단일 루프 안테너만으로도 충분하기 때문에 (실제로 HF 안테너는 여러 겹의 안테너를 코일 형태로 감는다. 이로 인해 제작 공정이 쉽지 않다.) HF 보다 훨씬 좋은 성능을 보일 수 있고 Gen2 anti-collision 알고리즘이 HF의 프로토콜 보다 훨씬 우수하다.


       UHF Gen2는 너무 먼거리에서 읽힌다

해답: 거리는 결국 안테너 설계의 문제이다. UHF는 안테너의 설계에 따라 장거리와 단거리 모두 다 사용할 수 있다. (HF far-field 로는 만들 수 없다.)


       UHF Gen2는 노이즈에 약하다

해답: 노이즈와 간섭 문제 역시 far-field의 문제이다. Near-field에서의 영향은 거의 없다.

UHF Near Field 의 장점이라면 기존에 설치된 UHF RFID 인프라를 태그 안테너와 리더 안테너만 교체하면 그대로 쓸 수 있다는 것이다.

다음 동영상을 보면 UHF 에서 안된다고 하던 수분에서의 읽기라든지 간섭 문제라든지 하는 문제점을 모두 해결한 것을 볼 수 있다.

혹시 Near Field UHF 에 대한 상세한 내용을 알고 싶으시면 다음 논문을 참조 바란다.


'기술 관심 > RFID' 카테고리의 다른 글

디바이스 미들웨어 1 - RFID 미들웨어를 넓게 보자  (0) 2008.05.09
RFID Middleware is Extinct.  (0) 2008.03.06
Near Field UHF Versus HF  (0) 2008.02.28
Near Field UHF - Manufacture  (0) 2008.02.26
Near Field UHF - Pharma  (0) 2008.02.26
Near Field UHF 기술 - Item level tagging  (0) 2008.02.25
Trackback 0 Comment 0