QUESTION: So any standard requirements and agreements by different industry clients before Antenna design as a target? → Are there standards, other agreements, or other shared practices in different industries about selecting a reader antenna for an application?
ANSWER: Unfortunately there are no standards or such. Even within an industry, and even within a type of RAIN application inside an industry the required read zones are different. Antenna manufacturers and experienced system integrators have accumulated knowledge of some best practices. But the starting point is still to look at each installation as an individual project.
QUESTION: What is the best RFID antenna option for reading a large tag population
ANSWER: If the goal is the quickly read a large/dense tag population, i.e item level within a carton, we would point customer in the direction of a high gain, focused antenna like the A5060 or in special cases to our multiple-input multilinear patch array panel the veRFIDa! Depending on distance you may see read volumes of 400-1000 tags within a 10 second read period.
QUESTION: Is there a linear polarised UHF Tag on the market? If yes, what kind of application is it for?
ANSWER: Most common RAIN RFID tag antenna type is dipole antenna and they are mainly linear. The antennas are not ideally linear, but radiate usually a little bit in other orientations. As a rule of thumb: the thinner the tag antenna is, the more linear it is. Most tags can not be read, or can only read at short distance with linear antenna if polarizations mismatch. There are some dual-direction tags which have two sets of dipoles and are capable of receiving signal from all directions.
QUESTION: What's the significance of using RHCP compared to a normal CP Antenna? → What is the benefit of using a RHCP antenna instead of a normal CP antenna?
ANSWER: Both Right Handed Circular Polarized (RHCP) and Left Handed Circular Polarized (LHCP) antennas can be considered to be normal. When a single antenna is used in an area, both RHCP and LHCP can be used equally well. The handedness can be utilized when 2 antennas are used in the same reading zone. Using one RHCP and one LHCP minimizes the interferences from one antenna to another. This improves the reliability of the RAIN RFID system.
QUESTION: What is the maximum read range with Near Field Antenna? And what could be safely assumed as “no-read” distance?
ANSWER: The used power also has a significant effect on the read range. Typically the near-field antennas can be set to read up to 1 meter distance. With a lower power setting the read range can be minimized to be maximum of 10s of cm.
QUESTION: Antennas are usually specified for maximum power for input, say 2W. What happens if we send to antenna 4W from the Reader?
ANSWER: The maximum power ratings are related to the antenna's internal circuitry. If power is exceeded, the antenna loses its performance more rapidly. The more the power is exceeded and the longer the time the power is exceeded, the bigger the risk to reduce the antenna's performance, or to damage it.
FOLLOW UP QUESTION: Generally, most UHF RFID readers will not deliver power higher than 33 dB (2 Watts), so applying more than 33 dB with a standard UHF RFID reader is difficult?
ANSWER: Absolutely, but with upcoming regulation changes like the ETSI upper band and other regional variations, we may see up to 4W transmission powers.
QUESTION: What kind of Antenna is suitable for Railway applications, especially when deployed on trains that conform to the EN50155 Railway Standard?
ANSWER: While any particular antenna may not explicitly state EN50155 certification, there is a list of adjacent ratings that can be used to filter for suitability. Look on the spec sheet or contact suppliers for IP6X(7/8/9) environmental ratings, UL94 fire resistance, vibration testing etc. Typically electrical/EMC/radiation tests must be done on a system level as RFID antennas are in isolation passive elements. We typically point customers towards our A5010 or A5020 antennas as a starting recommendation.
QUESTION: Can I use a parabolic antenna If I wish for very high directivity and Gain?
ANSWER: Parabolic antenna could indeed provide high directivity and gain. But, the limitation is most likely the allowed radiating power from local radio regulations. The limit can be achieved with a common RAIN reader and patch antenna. Also, a patch antenna structure is simpler than a parabolic antenna structure. Thus, in practice, parabolic antennas are (almost) never used in RAIN applications. If high directivity is needed, the common solution is to use a multipatch antenna.
QUESTION: RFID security gates typically use far-field antennas. Is it possible to use near-field antennas for a single RFID lane (1m width) to increase reading accuracy, considering that the human body is one of the factors affecting RFID accuracy?
ANSWER: With the right antenna selection a desired read range can be achieved (within some reasonable limits). For a 1 meter range, the optimal solution could be a mid-range antenna, that has both near-field and fai-field features. Times-7 can offer also mid-range antennas.
QUESTION: Do you offer antennas with switching polarization?
ANSWER:
QUESTION: I built a smart wastebasket with RAIN reader functionality. I noticed that 1 antenna only did not provide a reliable reading. I know that the reflection pattern inside the basket can be complex and also change when different items are inside. After installing a second antenna, the read performance got even worse. The first antenna was on the bottom, and the second at the side. The waste material is plastic and paper. The wastebasket dimensions are 100x40x40 cm. What happened? What do you suggest?
ANSWER: The reason for reduced readability is most likely interference in one way or another. The read zone dimension is fairly small so one antenna easily picks up the signal from the other. If the 2 antennas use the same antenna port (power splitting) the interference pattern from the 2 antennas would almost certainly create severe blind spots - areas in which the 2 signals cancel each other and where a tag could not be read. If 2 readers are operating at the same time, it is possible that the weaker tag responses are buried under the stronger reader signals.
One solution could be to use multiplexing. Reading with multiple antennas, but one at a time. This way a signal from one antenna would not interfere with the other antenna. In small space smaller reader power, or shorter range antenna is likely more reliable than high power and (lng range) far-field antenna.
At Voyantic.com at the bottom of page https://voyantic.com/rfid-in-healthcare/ there is a video “Analyzing tag population with Tagformance Pro”, the context is different but problem is very similar,
QUESTION: It was mentioned that UHF NFC antennas can offer reading capability on objects regardless of whether they're metal or liquid. Would we need specialized UHF labels to take advantage of this? Or would the below example work(where normally far-field antennas such as A5010 might not be able to read such tags when applied to metal/liquid items)?
-HID Omni-Id IQ400P on water bottles or Metallic objects."
ANSWER: The primarily magnetic fields that NF antennas use are not as readily absorbed or blocked by water content or metallics in comparison to far-field electric fields. This means that they are not reliant on specialized tags to prevent detuning.
https://www.times-7.com/blog/2020/08/17/why-uhf-rfid-struggles-to-read-liquid-assets/
https://www.times-7.com/blog/2020/04/14/rain-rfid-near-field-antenna-how-to-create-a-close-proximity-read-zone/
QUESTION: Is it possible that by putting a tag on a metal pole the pole itself could become a kind of antenna for the tag? Experience tells me that the reading distance of the tag in the frontal direction is much less than if you point the antenna in the direction of the pole (the tag, in that case, is oriented at 90°)
ANSWER: A metal pole close to the tag would affect the tag’s antenna. In a way become a part of the tag. Effect can be harmful, but it can also be utilized. The effect is utilized for example in tool tagging. https://landing.voyantic.com/tracking-tools-with-rain-rfid-webinar-on-demand
QUESTION: What is the future of UHF RFID in terms of new applications?
ANSWER: There has been a large update of RFID deployments in retail. With the EU looking to mandate digital product passports by 2030, and RFID being a great option to use as a digital passport, we are starting to see lots of interest in this area. We are also seeing the use of RFID vertically on a broader scale across industries, and also looking to enhance areas of delivery outside of pure inventory management, such as enhancing customer experience.
QUESTION: What physical phenomenon is responsible for RF tags sometimes being unreadable even when the distance between the antenna and the tag is around 10 mm?
ANSWER: At a 10 mm distance the tag is at the near-field area. For such a short range both the tag and the reader antenna must have good near-field properties. Most RAIN applications aim for reading distances that are 30 cm or longer. Tags and reader antennas don’t necessarily have good near-field properties.
To submit any further questions, please get in touch with us at sales@times-7.com