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Near Field Communication (NFC) technology and measurements - Part 2: NFC RF measurements

3/14/2011 04:11 AM EDT
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zeeglen
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re: Near Field Communication (NFC) technology and measurements - Part 2: NFC RF measurements
zeeglen   3/17/2011 7:34:02 PM
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You are right, took some distance for the electric and magnetic fields to stabilize in far-field to 377 ohms free space impedance, but nothing has changed. Read the article again and note at the beginning the specific reference to "magnetic field induction". Also note the figures showing magnetic coiled loops for transmit and receive functions. This system is more like an air-core transformer with windings in individual and separable devices. It is still near field magnetic coupling.

StevenHunter
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re: Near Field Communication (NFC) technology and measurements - Part 2: NFC RF measurements
StevenHunter   3/17/2011 4:35:47 PM
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When I went to school, several decades ago, near-field meant that transmission was in the magnetic field, not by EM waves. This seems to be short range communication, not near-field.

Roland.Minihold
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re: Near Field Communication (NFC) technology and measurements - Part 2: NFC RF measurements
Roland.Minihold   3/17/2011 1:45:42 PM
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Replies to the comments above: NFC communication at 13.56 MHz should not be affected by a communication in the 2.4 GHz band and vice versa (at least not with an appropriate design). Parameters for Figure 16 (NFC Operating Volume): D1 10 mm D2 20 mm D3 20 mm S1 5 mm S2 0 mm S3 0 mm So in reality the NFC Operating Volume is a truncated cone with an upper diameter of 20 mm, a lower diameter of 10 mm and a height of 5 mm. These paramters a still subject to change by the NFC Forum. Roland Minihold Rohde&Schwarz

Robotics Developer
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re: Near Field Communication (NFC) technology and measurements - Part 2: NFC RF measurements
Robotics Developer   3/15/2011 3:12:02 PM
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Really nice level of detail regarding the testing and the setups being used! Figure 16 is not completely clear to me but I am assuming that it makes more sense to those in the know. For example, what are the typical numbers for the various parameters shown in the diagram?

Luis Sanchez
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re: Near Field Communication (NFC) technology and measurements - Part 2: NFC RF measurements
Luis Sanchez   3/14/2011 9:00:28 PM
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Quite interesting note. It's good to know which are the kind of measurements that have to be done when referring to NFC technology. Now... I wonder how is an NFC communication affected by the 2.4GHz spectrum? I guess not too much since NFC will be working in a very different one correct? 13.56MHz according to the previous article. So... I think we can very well combine these two kinds of wireless circuits in to one product. And when it comes to some testing measurement one radio can be tested while the other one is turned off and then viceversa and finnaly to measure when both are working as a stress test.

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