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Smart Shelf™ & the Internet of Things

January 24, 2020 8:49:25 AM EST

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

 

SMART SHELF™ & THE INTERNET OF THINGS

Author: Dr. Den Burnside CTO and Founder of NeWave® Sensor Solutions and Emeritus Professor at the Ohio State University

 

NeWave® Sensor Solutions was recently interviewed for the  Discovery Channel’s new web and Facebook program: “Technology is Changing How We Live ” , sponsored by DeVry University. NeWave’s Smart Shelf™ was selected by the Discovery Channel to showcase future technology in “Cashier Free Retailers” and as an excellent example of a smart device enabling the  Internet of Things (IoT).  We recommend opening links in Internet Explorer.

 

Why is that important? Let’s examine what is the definition of the Internet of Things and the attributes of NeWave’s Smart Shelf.

 

 “Internet of things
From Wikipedia, the free encyclopedia

 

Drawing representing the Internet of things

 

The Internet of things (IoT) is the inter-networking of physical devices, vehicles (also referred to as “connected devices” and “smart devices“), buildings, and other items—embedded with electronicssoftwaresensors, actuators, and network connectivity that enable these objects to collect and exchange data.[1][2][3] In 2013 the Global Standards Initiative on the Internet of Things (IoT-GSI) defined the IoT as “the infrastructure of the information society.”[3] The IoT allows objects to be sensed or controlled remotely across existing network infrastructure,[4] creating opportunities for more direct integration of the physical world into computer-based systems, and resulting in improved efficiency, accuracy and economic benefit in addition to reduced human intervention.[5][6][7][8][9][10] When IoT is augmented with sensors and actuators, the technology becomes an instance of the more general class of cyber-physical systems, which also encompasses technologies such as smart gridsvirtual power plantssmart homesintelligent transportation, and smart cities. Each thing is uniquely identifiable through its embedded computing system but is able to interoperate within the existing Internet infrastructure. Experts estimate that the IoT will consist of almost 50 billion objects by 2020.[11]

 

Of course, that estimate for 50 billion objects is referring to devices connected to the internet. In this case, many see the future of the internet as being between machines without human intervention, which is described as being machine-to-machine (M2M) communication. Obviously, these machines must operate in autonomous mode in that there is no human involved. Besides being M2M, there are many attributes associated with the IoT such as being seamless, scalable, minimal impact on the web, provides valuable data and associated analytics, and web installation and maintenance. All of these features have been incorporated into our Smart Shelf solution.

 

Let us examine each of these attributes in terms of our Smart Shelf solution

 

NeWave’s Smart Shelf™ system provides information on shelf item movement to prevent merchandise out of stocks using its unique patented Wave® RFID antenna technology. In simple terms, when an item leaves the shelf, NeWave’s Smart Shelf sees it even when it is not tagged. Based on criteria set by the retailer for low inventory limits, the Smart Shelf software signals an alert in real-time that can be sent on-site to store managers, or remotely to merchandising and loss prevention personnel as well as suppliers. There is no need to tag items, so you get all the benefits of the solution, without the added labor, item tag and maintenance costs.  The Smart Shelf can also trigger an audio alarm message and a video capture alert within the store. The system strives to make it easy to get real-time in or out of stock shelf information available anytime to any authorized person or group.

 

To grasp this connection between Smart Shelf and IoT, one has to understand better how our Smart Shelf solution works from start to finish. First, our patented NeWave reader has been specifically designed for Smart Shelf applications in that it is based on an embedded small board computer as opposed to a simple microprocessor used by other RFID readers. This is extremely important in that the Smart Shelf reader must collect all the RFID tag data, process inventory data, compress the inventory data and then transfer data to the customer. Since all these functions require significant software and multiple processes that vary with an application running at the same time, it must be done within a computer and not a simple microprocessor. As a result, our reader comes with a complete set of Smart Shelf middleware and network software dramatically reducing solution installation complexity time and cost. In fact, the NeWave reader network software is designed to optimize the system performance and cost by employing the following powerful IoT attributes:

 

  1. M2M: Our NeWave reader is uniquely designed for Smart Shelf based on its embedded small board computer. It autonomously sends the compressed product inventory data directly to the customer’s server in a form that the customer can directly use within their existing inventory database. Thus, the customer defines the data format and transfer process making it ideal for their operation. As a result, the user has more timely and accurate shelf inventory data.
  1. Seamless: It is very difficult to design a system that is virtually seamless in that everything must continuously flow without human interruption from start to finish. For Smart Shelf, one simply connects the NeWave reader to the Smart Shelf hardware and then powers-up the reader. As our reader is powered-up, it automatically connects to the VPN Admin Server in NeWave’s Innovation Center. The reader is able to immediately connect in that we have pre-loaded the proper credentials into each reader. Once NeWave’s Admin server receives this initial credential information, it adds this reader system to its operational systems. In return, the Admin server sends a request to the installer to properly define his or her information, location, etc. The installer completes this form and then is informed to install the complete system using a bar code scanner interfaced to the reader. Once the installer completes the installation using the bar code scanner, the reader will automatically process this information and send an initial planogram file to the Admin Server. This initial information includes the product UPC code, product location, and associated RFID tray identification number. Once this file is received at the Admin Server, it will take this information and add the product name and dimensions. This will complete the planogram file that is automatically sent back to the reader as well as being stored on the Admin server. When this file comes back to the reader, it will start the normal inventory data collection and the installer will be informed that the installation has been completed; this process takes only minutes.  During the normal operation, the reader automatically checks itself, determines any maintenance issue and sends this information to the Admin server. Once this maintenance information is received at the Admin server, all the reader maintenance is performed over the web unless there is a hardware failure. If it is a reader hardware failure, the reader can be fully corrected by removing the SD card from the old reader and placing it into the news reader. Once this is done, the new reader will fully replace the old one. If the maintenance is associated with the Smart Shelf hardware, it can easily be corrected using the maintenance option with the bar code scanner. Finally, the main objective of the Smart Shelf is to eliminate out-of-stock. This is done by the reader automatically sending restock information to store personnel using a local NeWave Wi-Fi network within the store. Thus, the Smart Shelf system is a seamless solution.
  1. Scalable: Smart Shelf is designed to take advantage of our patented Wave® antennas that have been designed to cover a zone such as a 3’ or 4’ wide shelving section. The zones can be designed independently as adjacent or non-adjacent sections. The software has been designed so that each reader connects directly to the customer, Admin server and the local store network. Thus, each NeWave reader has software installed and operated in the same form making the software scalable as well.
  1. Minimal Impact on Web: The IoT becomes effective as more and more systems are attached to the web. This sounds great, but one has to be concerned about the impact on the web as these systems are added and sending important inventory data coming from 1000’s of our reader systems taking up huge amounts of bandwidth. In our case, the middleware processing within our reader optimally compresses the inventory data and only sends this very limited data on inventory changes a few times per day greatly reducing the amount of bandwidth required. Further, the customer takes this very limited data and integrates it within their existing database. Therefore, customer storage is virtually the same as used previously. The Admin server does not keep any inventory data. It simply stores the store information, shelving planogram, and needed maintenance issues. Therefore, it can easily handle a very large number of reader systems. Finally, the store re-stock information is stored in the reader and cleared as each product is re-stocked. Thus, there is very minimal impact on the web even though we may be running 1000’s of readers at one time.
  1. Provide Valuable Data: Our Smart Shelf system provides very valuable information to the customer. For example, the customer can determine the actual product inventory versus time. This can be used to determine very accurately when and what products need to be manufactured in a very timely way. Or, it can determine how well their products are re-stocked. Therefore, customers can be using “just-in-time” stocking of their products that will result in tremendous savings and a very positive return-on-investment. Finally, forensic analytics can be used on this inventory data to provide a whole set of new information such as season impact, weather impact, local customer habits, the impact of promotions and new products, etc. As the historical database grows the value of the inventory data collected will as well providing greater and greater business insight to the retailer and manufacturer.
  1. Web Installation and Maintenance: The middleware within the reader automatically knows if the Smart Shelf system has been installed or not. If not as stated earlier, the installer will simply be notified to start the Smart Shelf installation using the bar code scanner. Once this scanning process is completed, the Smart Shelf planogram is stored in NeWave’s Admin server and reader. This is an automatic process done over the internet as explained earlier. The Smart Shelf maintenance is performed by first using the bar code scanner to interrupt the reader from its normal operation. Once the maintenance person has been informed that the reader is now in maintenance mode, he or she can begin the various maintenance functions by using the bar code scanner. Note that once the maintenance is complete, the reader will again automatically upload the new potential planogram to the Admin server. The Admin server will again add the product names and dimensions and send this complete planogram file back to the NeWave reader. Note that this complete planogram file will then be stored in the reader and Admin server. Once these steps are complete, the reader will again return to normal inventory data collection. The NeWave reader comes with our unique middleware and software pre-loaded at no additional cost. The reader and Smart Shelf must be monitored by the NeWave Admin server as described earlier. This becomes a very important function in that the reader will automatically notify the Admin server of any system failure for immediate resolution. Since any failure of the reader short of a hardware failure can be corrected over the web, the customer can be assured that the system is functioning properly 24/7. This IoT benefit will be provided to the customer at a minimal monthly expense per system.
  1. Sensor Fusion: The seamless process used for Smart Shelf also takes advantage of sensor fusion in that we are using RFID to collect inventory data but we also use a bar code scanner process to do the installation and maintenance. Using this approach, we are taking advantage of the more valuable attributes of multiple sensors to create the best possible overall Internet of Things solution.

 

In summary, NeWave’s Smart Shelf has taken full advantage of the IoT attributes to create a unique cost-effective, reliable, accurate and easy to install and maintain shelf inventory solution that eliminates out-of-stock for each individual product placed in our Smart Shelf dispenser trays. NeWave’s Smart Shelf is unique in function and performance to prevent Out of Stocks offering a very significant business opportunity for retailers to enter the world of IoT.

 

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

 

1 Comments | Posted in News By Web Content1

A New Paradigm for Item - Level RFID Antennas

January 24, 2020 8:22:31 AM EST

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

 

A NEW PARADIGM FOR ITEM-LEVEL RFID ANTENNAS

Author: RJ Burkholder, Research Professor of Electromagnetics and RF at The Ohio State University

 

For years RFID system designers have trusted in the old reliable patch antenna to solve all their reader antenna needs. But how reliable is it? If you were to picture the beam, it would look something like a single beam, conical spotlight illumination pattern:

 

blog-01-01-300x153.jpg

 

This might be good if you’re looking for tags that are far away and in a specific and known location, but not good for tags that may be close to the antenna but outside the beam. Also, in most portals and item-level applications you don’t want to see tags that are far away, extraneous tags because that makes it difficult to localize the tags of interest.

 

What’s the solution? Well, we can crank down the power on the RFID reader, but that doesn’t solve the spotlight problem because the beam simply collapses in the same pattern. We can use more antennas to try and fill in the gaps in the illumination, but that is a Band-Aid solution at best, one never really knows if all the gaps are covered and it becomes a complex and expensive solution. Another possibility is the so-called “near-field antenna” (an oxymoron to antenna designers), but these have a very limited range, too limited for item-level RFID and they are not practical for covering large volumes.

 

The NeWave® philosophy is to not use a spotlight to do the job of fluorescent light. The latter does a much better job of uniformly illuminating a room or in the case of item-level RFID, the targeted tag read zone. By analogy, NeWave’s Wave® antenna is designed specifically for reliable high-diversity high-density coverage of a finite volume around the antenna, perfect for item-level RFID:

 

blog-01-02-300x186.jpg

 

It’s what we call a “distributed antenna” because it emanates waves all along its length like a fluorescent lightbulb. It also uniquely creates five interlocking beams traveling in different directions to provide much better polarization diversity than a single beam patch antenna. This design is ideal for item-level applications because tags can be localized to a certain volume around the antenna, and there are no gaps in the coverage.  Unlike the patch, due to the Wave’s illumination pattern, tags can be read regardless of their orientation.

 

The concept of an antenna that creates localized coverage of a given volume is a new paradigm for item-level RFID applications. It enables the establishment of zones within a larger environment such as a warehouse or retail store, making it possible to accurately locate tags quickly and perform inventories at the push of a button, the Holy Grail of item-level RFID technology.  Importantly the size of these zones can be adjusted from approximately 2 to 10 feet by a simple power adjustment providing great flexibility.

 

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

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RFID Reader Antenna Basics - Gain and EIRP

January 24, 2020 8:04:16 AM EST

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

 

RFID ANTENNA BASICS – GAIN AND EIRP

Author: RJ Burkholder, Research Professor of Electromagnetics and RF at The Ohio State University

 

In the last blog, I maintained that the antenna is the most important part of a UHF RFID system (see figure below). This is because the computer software, reader, and RFID tag are quite optimized now, and often outside the control of the system designer/integrator. Performance improvements must come from the antenna and its deployment.

 

image1-300x188.jpg

 

A typical UHF RFID inventory system

 

Before getting into the fine art of antenna deployment, it is first necessary to understand the basic principles of how antennas work and how the electromagnetic field radiated by an antenna fills and penetrates a given space. The main issues are polarization, fading, attenuation, gain, maximum EIRP (effective isotropic radiated power) and diversity. A good understanding of these issues will aid the designer in selecting the type and number of antennas, and where to put them for optimum performance.

 

The most basic characteristic of an antenna is its gain. This number is defined as the amplification of the antenna compared with an antenna that radiates equally in all directions. Hence, the units of gain are often dBi, which means “decibels relative to isotropic”. By definition, an antenna that has greater than 0 dBi gain does not radiate isotopically (the same in all directions) but has a gain pattern, sometimes referred to as its antenna pattern, or directivity pattern, as illustrated below.

 

image2-300x139.png

 

Gain patterns of a broad beam antenna and a narrow beam antenna.

 

The narrow beam antenna has a higher gain than the broad beam antenna, but a much smaller angular coverage. This is because both antennas radiate the same total power, and the gain pattern determines how this power is distributed. (Note that I am assuming here for simplicity that the antennas are 100% efficient. In other words, all of the power input to the antenna is radiated.) Our first principle is this:

 

  1. For the same amount of radiated power, increasing the gain of an antenna decreases the angular coverage.

 

A typical patch-type RFID antenna has a gain of about 6 dBi and looks like the broad beam pattern above. The designer might like to improve the read range by using an antenna with a higher gain, like the narrow beam antenna above, if angular coverage is not important. Unfortunately, it’s not that simple, but not because of the antenna.

 

This brings us to a very important concept in UHF RFID, namely, Effective Isotropic Radiated Power (EIRP). EIRP is defined as the amount of power that a theoretical isotropic antenna would emit to produce the peak power density observed in the direction of maximum antenna gain. For example, a typical RFID reader generates 30 dBm (decibels relative to a milliwatt) of RF power. Connecting a patch antenna with 6 dBi gain results in an EIRP of 36 dBm (30+6).

 

It so happens that 36 dBm is the maximum EIRP allowed by the FCC for electronic devices in the UHF RFID band. Now suppose I want to use the narrow beam antenna shown above, which has a gain of 12 dBi for example. Then the EIRP becomes 42 dBm which is over the FCC limit. I will have to reduce the reader's power to compensate. Our second principle is this:

 

  1. Increasing the gain of an antenna also increases the EIRP, which is limited by the FCC.

 

Therefore, for maximum read range, it doesn’t necessarily help to use a high gain antenna because you will have to reduce the RF power. The only advantage of a high gain antenna in RFID is to get a good read range with minimal power or to focus a beam in a limited coverage area.

 

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

Comments | Posted in News By Web Content1

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

 

RFID READER ANTENNA BASICS – OVERCOMING FADING WITH ANTENNA DIVERSITY

 

Author: RJ Burkholder, Research Professor of Electromagnetics and RF at The Ohio State University

 

In the last several blogs I maintained that the antenna is the most important part of a UHF RFID system (see figure below). This is because the computer software, reader, and RFID tag are fairly optimized now, and often outside the control of the system designer anyway. Performance improvements must come from the proper selection of the antenna and its deployment.

 

image1

 

A typical UHF RFID inventory system

 

Before getting into the fine art of antenna deployment, it was first necessary to understand the basic principles of how antennas work and how the electromagnetic field radiated by an antenna fills and penetrates a given space. The main issues are polarization, fading, gain, EIRP (effective isotropic radiated power) and diversity. A good understanding of these issues will aid the designer in selecting the type and number of antennas, and where to put them for optimum performance.

 

To review, we first explored the most basic characteristic of an antenna, namely, its gain. This number is defined as the directional amplification of the antenna compared with an antenna that radiates equally in all directions (isotropic). Gain is closely related to Effective Isotropic Radiated Power (EIRP). EIRP is defined as the amount of power that a theoretical isotropic antenna would emit to produce the peak power density observed in the direction of maximum antenna gain. EIRP is limited by the FCC to 36 dBm (decibels relative to a milliwatt) of RF power. As we saw, because of this limit, it does not always help to use a high-gain antenna because the EIRP will likely be exceeded unless the RFID reader power is reduced accordingly.

 

In the last blog we learned about the important characteristic of antenna polarization. Polarization defines the predominant direction of the electric field radiated or received by an antenna. It was illustrated that using a single patch-type reader antenna in a static scenario is likely to miss a significant percentage of tags simply because the polarization is misaligned. Even a circularly polarized antenna, which can detect a tag in any orientation transverse to the radiation direction, will miss tags that are oriented along the radiation direction as shown below.

 

new-project1

 

Two antennas provide polarization diversity for reading an RFID tag that a single antenna is not able to read due to the tag orientation.

 

This introduced the concept of antenna diversity, which means using more than one antenna to cover a given region in order to overcome the limitations of a single antenna. This brings us to the present topic of mitigating fading with antenna diversity. A polarization mismatch is not the only limitation of using a single reader antenna. Any single antenna has nulls where the radiated field is very low. Typically, an antenna is designed so that the nulls are towards the back and sides, and the main beam is free from nulls when the antenna radiates in empty space. However, in a realistic RFID environment, there is always multipath, as illustrated in the figure below.

 

image

 

Overcoming fading in a static environment with antenna diversity. Multiple RFID antennas provide spatial diversity for reading a tag that a single antenna is not able to read due to fading caused by multipath interference.

 

When multipath is present, due to reflections from the floor, ceiling, walls, and large objects, the electric field associated with each path can form an interference pattern. At points where the fields add in phase, constructive interference occurs and the pattern has a strong peak. Conversely, where the fields are out of phase, destructive interference occurs and the pattern has a null. If you've ever been at a stoplight and notice the radio reception has gone out, you are probably in a null. The reception comes back when your car moves out of the null sometimes just by moving a few feet. Wireless communications systems always have to deal with this issue. One solution is to use a different frequency because the interference pattern is highly frequency dependent. Changing the frequency moves the nulls. This is one reason why UHF RFID in North America covers a relatively large 26 MHz frequency band from 902 to 928 MHz. Readers can frequency-hop within this band to avoid interfering with other nearby readers, but also to help mitigate the effects of fading and improve the read rate.

 

Another example you have probably seen is a wireless router. They usually have at least two antennas. Some of the higher capacity routers have three or four antennas. The primary purpose of these antennas is to provide diversity in polarization and space. The interference pattern and nulls of an antenna are very sensitive to its placement and orientation. Another antenna placed just a few inches away will have a completely different pattern. This allows two or more antennas to have far better coverage of a multipath rich environment than a single antenna.

 

The same principles of antenna diversity apply to RFID readers. That's why most UHF readers have more than one antenna port. A general misunderstanding in RFID is that more antennas let you cover more area. That is true to a certain extent, but if you only have one antenna covering a given area, the read rate will suffer. For the best coverage, at least two antennas should cover any given point in the region of interest. This is illustrated below.

 

image1

 

Diversity-rich RFID coverage zone using for patch antennas on opposite sides. Overlapping beams from different directions provide spatial diversity as well as polarization diversity.

 

The example above shows an effective way to cover a fairly large area using four patch antennas (up to 20 feet). The antennas can be connected to the same 4-port RFID reader. This arrangement provides polarization diversity as well by tilting the beams. 4-port readers can be easily extended to 16 antennas using a multiplexing switch. There are many possibilities for antenna placement, but this basic concept of exploiting diversity will greatly improve tag reading performance.

 

In this blog, we have extended the concept of antenna diversity to include spatial diversity. The next blog will show how the Wave® antenna is ideally suited for zone coverage with a minimum number of antennas. Each antenna uniquely provides multiple overlapping beams in the zone surrounding the antenna.

 

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

Comments | Posted in News By Web Content1

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

.

RFID READER ANTENNA BASICS – THE WAVE® ANTENNA SOLUTION

Author: RJ Burkholder, Research Professor of Electromagnetics and RF at The Ohio State University

 

In the last several blogs I explained why the antenna is the most important part of designing a UHF RFID system (see figure below). This is because the computer software, reader, and RFID tag are fairly optimized now, and often outside the control of the system designer anyway. Performance improvements must come from the proper selection of the antenna and its deployment.

 

image1

 

Before getting to antenna deployment in RFID system design, it was first necessary to understand the basic principles of how antennas work and how the electromagnetic field radiated by an antenna fills and penetrates a given space. The main issues are polarization, fading, gain, EIRP (effective isotropic radiated power) and diversity. A good understanding of these issues will aid the designer in selecting the type and number of antennas, and where to put them for optimum performance.

 

To review, we first explored the most basic characteristic of an antenna, namely, its gain. This number is defined as the directional amplification of the antenna compared with an antenna that radiates equally in all directions (isotropic). Gain is closely related to Effective Isotropic Radiated Power (EIRP). EIRP is defined as the amount of power that a theoretical isotropic antenna would emit to produce the peak power density observed in the direction of maximum antenna gain. EIRP is limited by the FCC to 36 dBm (decibels relative to a milliwatt) of RF power.

 

As we saw, because of this limit, it does not always help to use a high-gain antenna because the EIRP will likely be exceeded unless the RFID reader power is reduced accordingly. Next, we learned about the important characteristic of antenna polarization. Polarization defines the predominant direction of the electric field radiated or received by an antenna. It was illustrated that using a single patch-type reader antenna in a static scenario is likely to miss a significant percentage of tags simply because the polarization is misaligned. Even a circularly polarized antenna, which can detect a tag in any orientation transverse to the radiation direction, will miss tags that are oriented along the radiation direction.

 

new-project1

 

Two antennas provide polarization diversity for reading an RFID tag that a single antenna is not able to read due to the tag orientation.

 

This introduced the most important concept of antenna diversity, which means using more than one antenna to cover a given region in order to overcome the limitations of a single antenna. Polarization misalignment is not the only limitation of using a single reader antenna. Any single antenna has nulls where the radiated field is very low. Typically, an antenna is designed so that the nulls are towards the back and sides, and the main beam is free from nulls when the antenna radiates in empty space. However, in a realistic RFID environment, there is always multipath due to reflections from the floor, ceiling, walls, and large objects that give rise to interference between direct and reflected fields. Fading occurs in regions where this interference is destructive, i.e., the fields are out of phase and tend to cancel.

 

Fading is overcome the same way as polarization misalignment, by using more than one antenna. The interference pattern and nulls of an antenna are very sensitive to its placement and orientation. A second antenna placed just a short distance away from the first will have a completely different pattern. This allows two or more antennas to have far better coverage of a multipath rich environment than a single antenna.

 

Antenna diversity is why most UHF readers have more than one antenna port. A general misunderstanding in RFID is that more antennas let you cover more area. That is true to a certain extent, but if you only have one antenna covering a given area, the read rate will suffer. For the best coverage, at least two antennas should cover any given point in the region of interest. This is illustrated below.

 

image1

 

Diversity-rich RFID coverage zone using four patch antennas on opposite sides. Overlapping beams from different directions provide spatial diversity as well as polarization diversity.

 

The example above shows an effective way to cover a fairly large area using four patch antennas (up to 20 feet). The antennas can be connected to the same 4-port RFID reader. This arrangement provides polarization diversity as well by tilting the beams. However, notice that the patch antennas are not ideal for covering a specified area due to their single-beam illumination. That is why it requires at least 4 antennas.

 

Is it possible to design an antenna that is optimized for the type of zone coverage shown above? The answer is the Wave® antennaThe Wave® antenna is ideally suited for zone coverage with a minimum number of antennas. It makes use of distributed radiation rather than beam radiation, as shown below.

 

screenshot_2019-03-11-rjb_blog6_3-5-19-pdf

 

The Wave® antenna has distributed radiation from multiple points along its length. The gain pattern shows multiple beams from one antenna.

 

The antenna has multiple radiating elements along its length that generate multiple overlapping beams in the volume surrounding the antenna. (In fact, 5 beams have been measured from the 7-foot version of the Wave®.) Compared to the patch antenna, which is like a spotlight, the Wave® antenna is like a fluorescent light bulb. It doesn’t have the long-range and directionality of a patch antenna but provides much more uniform coverage of the area around the antenna. Furthermore, the overlapping beams of the Wave® provide all 3 polarizations, whereas a patch antenna can only provide 2 at most. This makes the Wave® ideal for item-level zone coverage of densely populated regions of RFID tagged products in warehouses, retail stores, and portals.

A single Wave® antenna could cover an entire zone, but this antenna obeys the same physical laws as any other antenna and will have nulls and polarization misalignment at certain points within its range. Therefore, a second Wave® antenna is always used in tandem with the first antenna to provide the required diversity protection, as shown below.

 

screenshot_2019-03-11-rjb_blog6_3-5-19-pdf1

 

Wave® antennas cover the zone using only two antennas, providing natural polarization and spatial diversity.

 

As the figure shows, only two antennas are used to cover the entire zone, whereas at least five conventional patch antennas would be required to provide the same number of overlapping beams. It is noted that the two Wave® antennas do not need to be deployed on opposite sides of the coverage area, but can also be placed side-by-side with a small vertical offset. (Notice that the two antennas above are slightly offset in the vertical direction.)

 

In this and previous blogs, we have learned how to properly deploy antennas for diverse coverage of an RFID reading zone using the minimum amount of resources. Future blogs will focus on how these principles are extended to practical applications of item-level RFID in the logistics chain.

 

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

Comments | Posted in News By Web Content1

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

 

RFID READER ANTENNA BASICS – OPTIMIZING TAG SELECTION & DEPLOYMENT

Author: RJ Burkholder, Research Professor of Electromagnetics and RF at The Ohio State University

 

In the last several blogs I explained why the antenna is the most important part of designing a UHF RFID system (see figure below). This is because the computer software, reader, and RFID tag are fairly optimized now, and often outside the control of the system designer anyway. But let’s assume we have some say in the deployment of the RFID tags in the scenario of interest. For example, the reader antenna configuration may be more constrained due to space limitations, so proper tag deployment becomes more critical.

 

rjb blog 1.png

 

To review, we explored the basic characteristics of an antenna: gain, Effective Isotropic Radiated Power (EIRP) and polarization. Assuming the reader antennas are deployed for good illumination of the volume containing the tags, polarization is the most important consideration in the deployment of a tag. As we learned previously, polarization defines the predominant direction of the electric field radiated or received by an antenna. For a conventional antenna like the patch antenna, the polarization is always transverse to the direction of radiation outside the near-field region of the antenna. Therefore, the polarization of the receiving antenna(RFID tag) needs to be at least partially aligned with the polarization of the transmitting antenna, as illustrated below.

rjb blog 2.png

 

Alignment of the receiving antennas (RFID tags) relative to the polarization of the reader antenna (red arrow) and radiation direction (blue arrow).

 

In this example, the patch antenna is linearly polarized in the vertical direction (red arrow). The RFID tags are dipole antennas which are also linearly polarized. From left to right, the first two tags will have a good received signal, but the last tag on the right will probably not be excited. Similarly, if the antenna is horizontally polarized none of these tags would be excited – because the first two are oriented vertically and the third one is aligned in the radial direction. Circular polarization(CP) is a combination of vertical and horizontal polarizations with a 90° phase difference between the two. CP antennas can read tags that are at least partially oriented in any plane transverse to the direction of radiation (blue arrow). For this reason, CP patch antennas are the most common in UHF RFID applications. There is a cost, however, because CP antennas have a 3 dB reduction in gain for reading linearly polarized tags.

 

Similarly, CP tag antennas may be used with linearly polarized reader antennas. Ironically, CP tag antennas may not be the best choice for CP reader antennas because CP always has a left- or right-handed definition. If the CP tag is not correctly matched or oriented with respect to the CP reader antenna, it may not be detected. Often the only way to check this is by trial and error.

 

The radial direction away from the antenna is the worst possible orientation of a tag because it is orthogonal to both transverse directions. RFID tags should be mounted transverse to the radial direction from the reader antenna as much as possible, and never along the radial direction.

 

Using more than one antenna certainly helps the situation as shown below. As discussed in previous blogs, this introduces antenna diversity and polarization diversityRFID readers typically have more than one antenna port for this reason. They cycle through the antennas to maximize the total number of reads in a given coverage area. If one antenna polarization is not aligned with all of the tags, it is likely that one of the other antennas is aligned.

 

rjb blog 3.png

 

Two antennas provide polarization diversity for reading an RFID tag that a single antenna is not able to read due to the tag orientation.

 

Many of the above issues associated with conventional patch antennas are overcome by the specially designed Wave® antenna as described previously and shown below. The multiple overlapping beams of the Wave® antenna naturally provide spatial and polarization diversity. For this reason, it is the obvious choice for item-level RFID systems. The Wave® antenna virtually eliminates read errors caused by misaligned tags.

 

rjb blog 4.png

 

The Wave® antenna has distributed radiation from multiple points along its length. Tags in virtually any orientation are readable.

 

Besides the deployment of tags relative to the reader antennas, it is equally important to choose the proper tag for the application and mount it on the item in a way that facilities reading. For example, standard printed RFID tags should never be put directly on metal surfaces or in liquids. A tag on a metal surface will be shorted out, and a tag in a liquid will probably not be detected due to the attenuation of the RF signal. There are specially designed tags that can be placed on metal or other highly conducting surfaces. They always employ some sort of spacer between the antenna and the metal as shown below. The tag then operates similar to a microstrip patch antenna or folded dipole.

 

rjb blog 5.png

 

RFID tags that are designed for metal surfaces always have a spacer between the antenna and metal. The tag on the right is a standard printed tag on a foam spacer, rather than a custom-designed tag.

 

In fact, a standard printed tag can be used effectively on a metal surface simply by placing a foam spacer between the tag and metal as shown on the right in the above figure. The spacer should be at least 1/8” thick. This type of tag can also be used on plastic bottles containing liquids.

 

Standard RFID tags work well when attached to paper, cardboard, fabric, thin plastic or glass, assuming there is no metal in close proximity to the tag. They can also be detected through these materials, making it possible to completely hide the tag. Common approaches are to put the tag inside cardboard packaging or sandwiched inside a label. They can also be easily RFID Expert’s Corner embedded inside a thin plastic card such as a credit card or ID badge. Recently there has been a trend to put RFID tags in clothing, even embroidering the metallic antennas into the fabric. This works well unless the tag is in direct contact with the skin; some sort of spacer such as an inner liner or another layer of clothing should be present to prevent this.

 

RFID tags may also be embedded in thick dielectric materials, such as plastic, rubber, wood, concrete or asphalt. However, these materials tend to detune the tag antenna causing reduced performance. It is therefore advisable to use specially designed tags for these materials. Even so, the RF waves may not penetrate the material as well (depending on the dielectric strength and conductivity), so some degradation in performance is to be expected.

 

Lastly, attention should be given to the environment surrounding the tag. Metal will block the RF signal, and other materials can be highly attenuating. The more material there is between the tag and reader antenna, the more the attenuation. Also, tags that are very close to other tags can degrade their performance. For example, a number of thin clothing items that are stacked with all the tags in the same place and with the same alignment will make it very challenging to read all of the tags. In this case, it would be helpful to have the tags randomly placed on the items.

 

To summarize, the following is a list of dos and don’ts for RFID tag deployment.

 

Dos:

  1. Mount tags on or in thin non-conducting materials such as paper, cardboard, fabric, plastic or glass.
  2. Orient the tags so that they are at least partially transverse to the radial direction from patch reader antennas. Using the Wave® antenna instead of patch antennas avoids this problem.
  3. rjb blog 6.png
  4. Use CP reader antennas with linearly polarized tags, or CP tags with linearly polarized reader antennas. The Wave® antenna can read either.
  5. Use special-purpose tags for metal surfaces, liquids, and for embedding in thick materials.
    - Conventional tags may be used on metal surfaces with a 1/8” foam spacer.

 

Don’ts:

  1. Avoid mounting tags along the radial direction from patch reader antennas.
  2. Do not mount standard printed tags directly on metal surfaces, in liquids, or on bottles containing liquids.
  3. Avoid metal and thick materials in the vicinity of the tag that may block or attenuate the RF signal from the reader.
  4. Do not place tags in direct contact with or very close to other tags. Future blogs will focus on how these principles are extended to specific practical applications of item-level RFID in the logistics chain.

 

For New Wave product information, or to order New Wave RFID antennas, visit https://www.arcantenna.com/antenna-manufacturers/newave-sensor-solution

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Maximum Weight the Times-7 A5530 Mat can Withstand

December 2, 2019 10:17:12 AM EST

The Race Timing Mat, also known as P/N A5533, is designed to support moderate loads such as runners, cyclists, hand trolleys, and carts. In other words, carts and bicycles utilizing rubber wheels and the occasional vehicular traffic with pneumatic tires should be supported by the mat antenna. The weight load should not exceed 100 psi (7 kg/ cm2) and the maximum distributed load on the mat should not exceed 1100lbs (500kg). If you were to surpass the weight limitations, the antenna will no longer be able to function properly. On another note, care must be taken to ensure the mat is installed on a smooth, hard, flat surface. Make sure that the mat surface is not damaged by sharp objects such as steel-edged wheels, stone chips or glass fragments, etc. This will ensure the longevity of your antenna.

 

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For further information regarding the application of this product, you can always reach out to our tech support!

Tech Help at Arcadian Inc. / arcantenna.com can be reached by email at techsupport@arcadianinc.com

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Laird Introduces FLEXMIMO - The World’s First Embedded PIFA Antenna for Wi-FI MIMO Applications
Provides a Flexible, Easy to Install 2.4/5 GHz, Dual Element PIFA Antenna for Wi-Fi MIMO Applications

 

LairdJuly 18, 2018 – Laird, a global technology leader, today announced the FlexMIMO - the industry’s first flexible PIFA antenna, part # EFD2455A3S-10MHF1, for Wi-Fi MIMO applications. The FlexMIMO has two integrated 2.4/5 GHz dual-band antenna elements specifically designed for 802.11 MIMO applications, such as automated equipment, medical devices and a myriad of Internet of Things (IoT) use cases. The FlexMIMO is based on a Planar Inverted-F Antenna (PIFA) structure, comprised of two mylar antenna elements with a foam core, resulting in a low profile, flexible antenna. 

 

The FlexMIMO can be mounted in a wide range of applications. Laird’s patented, flexible PIFA antenna structure allows for the use of the antenna on flat and curved surfaces (concave or convex), providing greater flexibility in design and superior antenna gain and performance.


“Laird is simplifying the technical requirements needed for implementing the two antennas for 802.11 MIMO radio applications,” said Jonathan Kaye, Senior Director, Product Management, Laird. “The FlexMIMO is designed with the ideal orientation and spacing between the two integrated antenna elements, so it’s already optimized for 2x2 MIMO radio performance, giving our customers the best possible range and throughput for their wireless applications, without having to worry about antenna isolation and orientation."

 

The FlexMIMO has a layered, compact design that is about the size and thickness of a quarter, which reduces the overall solution footprint. With an operating temperature range of -40° C to +85° C, the 2.4/5 GHz model is specifically designed for 802.11n/ac/ax applications that use MIMO or Wi-Fi Diversity. The FlexMIMO has low ECC performance, enabling best in class throughput and range performance, and is certified for use in Laird’s 60 Series of Wi-Fi + BT modules. Laird’s FlexMIMO antenna is available immediately, as well as engineering samples. Depending on a customer’s unique requirements, customized versions are also available. The FlexMIMO is the latest in a family of antenna solutions that are engineered to provide unmatched quality and flexibility while solving real-world antenna design challenges.

 

About Laird 

Laird is focused on providing systems, components, and solutions that protect electronics from electromagnetic interference and heat, and that enable mission critical connectivity through wireless applications and advanced antenna systems. Laird’s products are critical to all sectors of the electronics industry, including transportation, industrial, medical, telecommunications, computing, and the mobile device sectors. Laird employs nearly 9,700 employees at 48 locations, including 20 engineering and manufacturing facilities, 18 research and design centers, and 10 sales and administrative offices, in 19 countries worldwide.

 

Click here to see an overview of Laird's first ever PIFA antenna for Wi-Fi MIMO Applications! 

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What is an NMO Mount? How is it used? Do you need it?

 

Chrome Magnetic NMO Mount

 

An NMO mount, pictured to the left, stands for "New Motorola." It's a popular type of mounting base that's frequently used when installing mobile antennas. It comes in two different installation types, thru-hole and magnetic. Thru-hole mounts typically need a small hole, around 3/8" to 3/4", to be drilled through the surface the mount would be resting upon. It's the best choice for an extremely rugged installation. The thru-hole mount comes in two colors, chrome and brass. The magnetic mount is similar to the thru-hole mount, but the applications are different. The magnetic mount can be placed onto any metallic surface and has a pull of about 8 lbs. It comes in two colors, black and chrome, and won't damage your appliance since its application doesn't involve a drilled hole.

 

The idea of the NMO mount is simple.  NMO mounts are devised to have a standard threaded connector where you screw on the antenna of choice to the mount. It connects to the antenna and provides the antenna cable as well.  There are a large number of antennas that are built to screw on to the NMO mount, simply look for an antenna with an NMO base. 

 

NMO mounts have two waterproof seals, so if installed right it should prevent the car from rusting out. The first seal, or waterproof gasket, is placed directly against the metal of your vehicle or another metallic surface, while the second sits inside the antenna. This keeps the connection point of the antenna dry. You would also be delighted to know that once you connect an antenna to this mount, it isn't permanent, therefore, you can remove the antenna and switch it with a different one.

 

Once mounted, the NMO mount only occupies 1/4" of the height above its mounting surface, meaning that it's low profile and unobtrusive. Recently, we've unveiled 15 new NMO mounts from RFMAX, ranging from brass thru-hole mounts to chrome magnetic mounts, so don't forget to check that out! The thru-hole mounts begin with RNMOT while the magnetic mounts start with RNMOM. Enjoy! If you have any other questions regarding the topic don't be afraid to reach out!

 

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For further information regarding the application of this product, you can always reach out to our tech support!

Tech Help at Arcadian Inc. / arcantenna.com can be reached by email at techsupport@arcadianinc.com

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Inquiry: Does a roof-mounted multi-band antenna need to be grounded for lightening or surge protection?

GJ-RSF-DB-G4W-TTT: RFMAX Shark Fin Antenna

We recently had a client reach out to us about an antenna that would work well for their Panasonic Toughbook 20. We had recommended the GJ-RSF-DB-G4W-TTT antenna because of its ability to handle the connections being broadcasted and received in rural areas with its optimization for combing 1575 MHz GPS, 698-2700 3G/4G/LTE cellular data communication and 2.4 / 5 GHz WIFI/WLAN. They then went on to ask whether the antenna would need to be grounded for lightening or surge protection. Fortunately, they do not need to be grounded because the antennas are encapsulated in a plastic housing and isolated from the vehicles’ metal surface.

 

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For further information regarding the application of this product, you can always reach out to our tech support!

Tech Help at Arcadian Inc. / arcantenna.com can be reached by email at techsupport@arcadianinc.com

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