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Helps the user understand the various components in NFC and their mathematical significance. Very useful for discussions presented in the next module.

About the components

An NFC system consists of a passive network (the card/circuit with information) and an active circuit. We must also take into account the environment surrounding the device. A working knowledge of these three componenents is essential to understanding the inner mechanics of near field communication.

The active circuit

The active circuit has a transmitting antenna that broadcasts RF waves and a number of electrodes that read values corresponding to how the environment reacts to the RF waves. All the processing power is centered in this active circuit and that is where the decoding will take place. This would be considered the reader in the traditional sense. In the following mathematical discussion, the electrode voltages of the active circuit will be values in a vector v1.

The passive network

The passive network consists of a series of electrodes which are attached to impedances with values of infinity or zero (open/closed switches). This network might be located inside a phone or other device and is associated with the client side identification. The configuration of the passive network uniquely identifies the user, and thus, our problem becomes one of reverse engineering in which we try to determine the impedances. In our analysis, the passive network voltages are stored in the vector v1 and the impedances are represented by the matrix Y1. Since we are assuming no mutual impedances, this is a diagonal matrix. Rather than using infinity, we have represented the open switches with the very high impedance value of 10,000 ohms.

The environment

The “evil channel” is our environment. It converts our beautiful binary impedances into ugly complex voltages. It is our job to understand its effects and make sure that our output is decipherable. The channel matrix we used was given to us and was measured experimentally. It can be modeled by a large square matrix which is of size N x N where N is the total number of voltages (in this case 41). The matrix is labeled Ys and is divided into 9 separate matrices, each representing the mutual interaction of different elements in our matrix.

For example, the elements in matrix W12 would reperesent how the electrodes with voltages v1 interact with the electrodes with voltages v2. Consequently, our answer lies in simplifying this matrix and trying to nullify it’s effect on the input (the Y1 matrix).

Problem analysis

As previously stated, the relationship between input impedences and output voltages is non-linear by nature. Thus, our task will be to find some underlying patterns between input and output so that we may adequately decode the voltage values. When presented with a problem as open-ended as this, a number of techniques can be employed. We must make a preliminary analysis of the data through the use of well-constructed plots and principle component analysis.

Questions & Answers

how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Elec 301 projects fall 2011. OpenStax CNX. Jun 18, 2012 Download for free at http://cnx.org/content/col11431/1.1
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