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Electronics => Electronics => Topic started by: nitroxextreme on December 02, 2008, 12:11:32 AM

Title: Measuring RFID Signal Strength
Post by: nitroxextreme on December 02, 2008, 12:11:32 AM
I am currently working a project that needs to be able to read the signal strength of passive RFID tags.  The concept is that the receiver will be placed between two passive RFID tags.  These tags will be roughly 10-20 ft apart, the receiver will effectively have to work at a range of 5-10ft.  In the best circumstances the reader will be able to receive both of the signals and their strengths.  However, if this is not possible being able to read one signal with a strength will be adequate.

I have be doing some research, but have only found extremely overpriced commercial products(such as RFID radar).  Even when emailing some of the companies to ask for a suggested product returns not even a response.

Any information or suggestions are appreciated
Title: Re: Measuring RFID Signal Strength
Post by: Admin on December 04, 2008, 06:24:06 AM
What you are asking for is very unrealistic. You'd be lucky to get even 5 ft with a passive RFID! Those commercial readers aren't overpriced, just expensive and rightly so.

The IEEE Robotics and Automation Society released a Special Issue on RFID earlier this year. It was a great article that explained the state-of-the-art in RFID technology as well as state of RFID in the industry. I *highly* recommend you finding a copy and reading it.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1705602
Title: Re: Measuring RFID Signal Strength
Post by: nitroxextreme on December 04, 2008, 03:24:26 PM
OK so now it is time for me to rethink a few things...I need to find out what i can use for the "longest" range on passive or semi-passive sensors.  And of course what reader would be able to read that specified sensor.

I am currently looking into finding the paper you refered to, at this point no luck, but when i do I will post a link so others can gain benefit.  However, do you have any other suggestions for useful sites that I could do some more research on?
Title: Re: Measuring RFID Signal Strength
Post by: Admin on December 04, 2008, 09:38:51 PM
That issue I linked earlier was the wrong one . . . the one I'm thinking of came out in mid-2008 if I remember right. I can't remember the article name(s), so had no luck finding it on google.

Here are a few reads though:
http://www.spectrum.ieee.org/search?queryText=RFID&RadioGroup=Radio1
Title: Re: Measuring RFID Signal Strength
Post by: Half Shell on December 05, 2008, 09:11:17 AM
A few questions for what other "passive" markers/beacons you could use:

How obtrusive can it be? Should it be hidden from sight? What's our size range? Can it absolutely not be powered?