Picking nits
I'm getting tired of thesis editing. I decided to take a break when one of comments was that I should change "the total power radiating from an antenna" to "the total power radiated from an antenna." Perhaps I'm just picky, but putting it in the past tense creates, in my mind, the implication of integrating over all time. However, if you're looking at the instantaneous power or time-average power, "radiating" is better.
But that's just my opinion.
My crankiness was not helped by reading the RFID Journal article on the recent brouhaha over RFID-generated EMI to medical equipment.
If you aren't aware, some dudes on the other side of the pond (specifically Erik Jan van Lieshout and Remko van der Togt of the Netherlands) tested the probability of RFID systems interfering with medical systems in a hospital. I knew from a discussion at the conference last summer that government agencies had gotten complaints to this effect and were investigating it. It was only a matter of time before people started doing studies.
This study showed that RFID systems could shut down vital equipment in a hospital (such as ventilators) at an average distance of 30 cm. However, some of the equipment affected was as far as 6 meters away. I am a bit surprised that, being done in the Netherlands, the systems were affected thusly. The EU has certification requirements for immunity or susceptibility, while in the US, the FCC doesn't require such immunity testing (and I think that applies to medical equipment as well, although there is a small chance that I'm wrong). Of course, the amount of power put out by a reader is not necessarily trivial.
I'm not a big fan of RFID Journal because it's primarily a trade magazine aimed at promoting business to buy into the RFID hype. They tend to steer clear of anything at all that smells of shortcomings or issues in the use of RFID, which is why I was suprised to see them even discuss the medical equipment issue. Of course, after I overcame my surprise at their change of heart, I realized quickly that the main point of the article was to nit-pick some issues.
Their main complaint is that all these articles don't explain that it's not the chips/tags/transponders causing the problems but the readers.
I agree that the coverage of this hasn't been the most accurate. However, even the IEEE Spectrum article on the topic, which generally has great technology coverage (cuz duh! They're writing for engineers!), implies that some of the problem emanates from the tags. It does a better job by mentioning both parts of the system.
I think it's a bit ridiculous to get upset over that. RFID is hyped as little tiny electronics that can magically check you out at Wal-Mart to the general public. Of course most people don't understand that there's a slew of equipment that goes into the indentification of the electronics. Even many highly educated engineers may not understand all that's involved, which is why I always give an overview of the entire system at the beginning of my talks on the topic. (If they get nothing else out of the talk, the audience can usually come away with an understanding of what RFID is.)
I generally didn't like the tone of the rest of the article, either. It felt, to me, like it was giving lip-service to the safety of the patients while trying to convince everyone that RFID was all well and good.
My thoughts are that RFID should never be placed near any vital medical equipment or where patients may come in contact with it. Period. I don't think vendors will do a good job of ensuring safety given that most of them don't understand electromagnetics and the issues surrounding electromagnetic interference. I think by expecting hospitals to begin conducting regular EMI sweeps to deal with the problems (which would most likely need to be done by EMI consultants to be effective), you're asking them to take on a huge expense which is only going to passed onto patients and still doesn't guarantee patients' safety.
But that's just my opinion.
My crankiness was not helped by reading the RFID Journal article on the recent brouhaha over RFID-generated EMI to medical equipment.
If you aren't aware, some dudes on the other side of the pond (specifically Erik Jan van Lieshout and Remko van der Togt of the Netherlands) tested the probability of RFID systems interfering with medical systems in a hospital. I knew from a discussion at the conference last summer that government agencies had gotten complaints to this effect and were investigating it. It was only a matter of time before people started doing studies.
This study showed that RFID systems could shut down vital equipment in a hospital (such as ventilators) at an average distance of 30 cm. However, some of the equipment affected was as far as 6 meters away. I am a bit surprised that, being done in the Netherlands, the systems were affected thusly. The EU has certification requirements for immunity or susceptibility, while in the US, the FCC doesn't require such immunity testing (and I think that applies to medical equipment as well, although there is a small chance that I'm wrong). Of course, the amount of power put out by a reader is not necessarily trivial.
I'm not a big fan of RFID Journal because it's primarily a trade magazine aimed at promoting business to buy into the RFID hype. They tend to steer clear of anything at all that smells of shortcomings or issues in the use of RFID, which is why I was suprised to see them even discuss the medical equipment issue. Of course, after I overcame my surprise at their change of heart, I realized quickly that the main point of the article was to nit-pick some issues.
Their main complaint is that all these articles don't explain that it's not the chips/tags/transponders causing the problems but the readers.
I agree that the coverage of this hasn't been the most accurate. However, even the IEEE Spectrum article on the topic, which generally has great technology coverage (cuz duh! They're writing for engineers!), implies that some of the problem emanates from the tags. It does a better job by mentioning both parts of the system.
I think it's a bit ridiculous to get upset over that. RFID is hyped as little tiny electronics that can magically check you out at Wal-Mart to the general public. Of course most people don't understand that there's a slew of equipment that goes into the indentification of the electronics. Even many highly educated engineers may not understand all that's involved, which is why I always give an overview of the entire system at the beginning of my talks on the topic. (If they get nothing else out of the talk, the audience can usually come away with an understanding of what RFID is.)
I generally didn't like the tone of the rest of the article, either. It felt, to me, like it was giving lip-service to the safety of the patients while trying to convince everyone that RFID was all well and good.
My thoughts are that RFID should never be placed near any vital medical equipment or where patients may come in contact with it. Period. I don't think vendors will do a good job of ensuring safety given that most of them don't understand electromagnetics and the issues surrounding electromagnetic interference. I think by expecting hospitals to begin conducting regular EMI sweeps to deal with the problems (which would most likely need to be done by EMI consultants to be effective), you're asking them to take on a huge expense which is only going to passed onto patients and still doesn't guarantee patients' safety.