Linear vs Circular RFID Antennas: Which is right for me?
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- เผยแพร่เมื่อ 20 ก.ย. 2024
- In this video, learn about the differences between linear and circular RFID antennas and figure out which is best for your application.
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Thank you for the video, It actually really precise and helpful for me to understand.
but I have a questions, as you mentioned Linear antenna has longer range than circular and its good if you can be able to predict the tag orientation, could you specify it in more detail about your meaning of tag orientation?
tags needs to line up in same format? or if in the box some RFID tags are attached bottom but next box attached on the left linear antenna still can read it?
Choong,
Yes, generally linear antennas have longer read range than circular because they do not have to rotate planes. Tag orientation refers to whether the tag is orientated on a box horizontally (the long end parallel to the ground) or vertically (the long end perpendicular to the ground). This video will walk you through orientation around 0:57 th-cam.com/video/D-AOOoSFj78/w-d-xo.html
To answer your last question, typically all the RFID tags should be facing the RFID antenna when they are being read or moving through the read zone. The face of the tag should face the "face" of the RFID antenna. Does that make sense?
Thanks for answer. I saw some video where man can move few degrees and signal was ok with linear. So on plane whitch is almost in same position with no acrobatics you will get better range with linear ? Can you say haw big difference in altitude can be ? Or angle
Correct, if you use a linear antenna with an RFID tag that is "lined up" in the same plane as the antenna's radiation pattern, then you will get longer read range (vs. using a circularly polarized antenna of comparable gain). However, it is difficult to speculate how much of a difference as well as how "far off" the tag can be from the linear antenna's radiation pattern before the tag reads start to be missed. As always, we recommend thorough testing before deploying any RFID system.
Jan Prejzek 7
Thanks sir
No problem, glad you enjoyed it!
sir what should be the minimum distance between the reader and antenna
Raj,
There typically isn't any requirements for minimum distance between a reader and an antenna, in fact, there are a few readers that have an integrated antenna (www.atlasrfidstore.com/integrated-rfid-readers/). The smallest antenna cable to connect the RFID reader to the RFID antenna that I have seen is about 1 foot, but a smaller one might be able to be made. I hope that helps!
can i ask,when i mesured the rssi used landmark system with circular polarization patch antenna,when i moved the antenna from (the right to the left ) and from (the the left side to the right side)of my landmark system the results are diffrent ? why? can be related to the left and the right circular polarization of the antenna ?
Abdo, There are a lot of different factors that can affect RFID tag attributes, particularly RSSI. Even slightly changing the angle of the antenna can have a visible affect on a tag's RSSI. Please see this article outlining some of these factors - blog.atlasrfidstore.com/improve-rfid-read-range.
Sometimes, the RSSI is not the best factor in determining read range, also check out this article that talks in depth about the pros and cons of RSSI. blog.atlasrfidstore.com/rssis-role-rfid
Thanks!
Will it be possible If I would create an antenna that would surround my whole door from, will it be able to detect the rfid that would pass in the door which is in the middle of the antenna?
Your idea might be possible depending on the amount of space you are trying to cover. A series of Harting Locfield antennas connected to a single reader and outlining a door frame MIGHT accomplish what you propose; but, you'd have to complete thorough testing to be sure. Here is a link to the antennas in question: www.atlasrfidstore.com/harting-ha-vis-rfid-antennas/.
@@atlasrfidstore But dont these output is a cylindrical pattern? would that mean that you might get reading from tags not passing through the actual door?
@@AMalas Unfortunately, door frame/portal applications always run the risk of capturing stray reads. In addition to carefully selecting, setting up, and tuning the RFID hardware that you may need, you'll likely need to use some software algorithms to filter out unintended/stray reads. For example, you could tell the system to ignore tag reads that show up under a certain level of RSSI and/or number of reads/second. In any case, thorough testing is needed - not just on a single door frame or portal, but on every one that is outfitted. Lastly, tag selection will be key to ensuring you get the right reads. You'd want a tag that gets enough range to be read when crossing the portal's threshold, but yet that doesn't give so much range that you pick it up from too far away.
Can i ask, which antenna would be the ideal for a marathon? a race...
Thanks for your question! There are a variety of antennas used in race timing. Mostly, either ground (mat) antennas or panel antennas either mounted overhead or on the sides of your finish line. The antenna you need depends on a variety of factors: The type of race you are timing, where you plan to tag your participants, and the number of participants you have.
Take a look at these race timing articles in the link below when you get a chance to learn more about anything race timing related! blog.atlasrfidstore.com/?s=race
Thank you for the answer, and I would like to ask one more thing, I need to record the time that the athlete passed the finish line. I would like to know how I can only pick up the moment when the athlete passes the finish line. Is there no risk of the RFID antenna picking up the TAG signal before the finish line? After all it has an "angle" where it picks up the signal right? Is there any way to capture the signal in a straight line?
That would be a benefit of using a linear polarized antenna. The radio waves from a linear polarized antenna can give you a more precise reading area because they typically have a narrower radiation pattern than the waves emitted from a circular polarized antenna.
Another way to be precise with your read point is through testing the antennas you have and adjusting them in a way that only reads tags in a certain area. You can use the RFID Power Mapper to “map” out where the radio waves are the strongest and also to find where the most interference is. See the Power Mapper here: www.atlasrfidstore.com/vulcan-rfid-power-mapper/
Thank you very much, that was a great help!!!
Hello again, I wonder what tag you indicate and it is worth having a UHF RFID printer? From your site, which set would you indicate? For example, a race with 500 atlets to run 5-10 Km.
can i augment the gain of microstrip patxh antenna 867MHz(rfid)? if the answer is yes ,than how?
The gain of an RFID antenna is determined by the antenna's design and set during its production; unfortunately, antenna gain cannot be changed once the antenna has been created. However, the RFID reader’s transmit power can be adjusted in almost every reader’s settings to increase or decrease the power output from your antenna (which will affect its read range).
Take a look at this blog that discusses how antenna gain and transmit power work together to determine total output power: blog.atlasrfidstore.com/conform-regional-regulations-using-rfid.
Also, here is a post on the various factors that will affect read range (including antenna gain): blog.atlasrfidstore.com/improve-rfid-read-range.
Can i ask, why is circular anthennas with helical used for "long" range instead of more range with linear anthenas (as you say) ?
Thank you
Jan, thanks for your question. We apologize for any confusion, but we do say that you'll get a longer read range with a linear antenna; however, we only recommend using a linear antenna when you can accurately predict the orientation and placement of the RFID tags for the given application. If you cannot predict the orientation of the RFID tags, then we recommend using a circularly polarized antenna (which will have a shorter range than a linear antenna of comparable gain). Please let us know if you have any other questions.
I dont understand exactly. What you mean by orientation. It mean it must be only straight vertically or it must be like set to one direction like East ? Like directional antenas ? Ofc when you wanna better reception you will use directional linear anthena on reciever ? :)
With regard to linear antennas and RFID tag orientation, we mean that the tags must "line up" with the linear antenna's radiation pattern. As shown in the video, linear antennas will transmit along a single plane (for the most part); so, you would "line up" the tag with the antenna's radiation pattern. Some quick testing will show how big a difference there is in terms of read range when a tag is within the same plane versus when it is rotated 90 degrees. Here is another TH-cam video of ours that talks about the same concept in a slightly different way: th-cam.com/video/rSbSYp2hexs/w-d-xo.htmlm13s.