# NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

## JDK1.0.2 simulations (1996-2001) => Electromagnetics => Topic started by: Taona on May 02, 2009, 10:58:30 pm

 Title: magnetic induction communication system Post by: Taona on May 02, 2009, 10:58:30 pm I need to simulate a magnetic induction communication system withtwo coils radius 10cm, Q factor 40,distance between centres 10cm,eficiency 96%, frequency of operation is 5khz, In the second instance the centres need to be misaligned by 10 cm i need to compare the difference with the first case.Of interest is how the magnetic field from the first coil induces current in the second coil under these different situations Title: Re: magnetic induction communication system Post by: Fu-Kwun Hwang on May 03, 2009, 12:29:12 am Simulation steps:1. The voltage can be assumed as Vo*sin(wt).2. The cureent in the loop can be calculated if the resistance R and the self inductance L of the coil are available.3. Then, The magnetic field distribution in the second coil can be calculated to get the total magnetic flux.4. The induced emf can be calculated from rate of change of magnetic flux.5. The induced current can be calculated from resiatance and self inductance of the coil.6. The induced current can generate magnetic field in the first coil. so the step 2-5 will repeated continuely (between coil 1 and coil2) until the result can be ignored.More information are needed:1.What is the resistance and the inductance of the coil?Please provide definition of Q factor and efficiency,too!2. Misaligned in which direction? along axial direction or perpendicular to it? Title: Re: magnetic induction communication system Post by: Taona on May 03, 2009, 07:36:36 pm thanks for the response,please see the attached diagram and information,thanks Title: Re: magnetic induction communication system Post by: Taona on May 03, 2009, 07:50:17 pm please see the alignment diagram attached Title: Re: magnetic induction communication system Post by: Fu-Kwun Hwang on May 03, 2009, 09:27:36 pm Information from your files:QuoteEfficiency n1 = Rs/(RL1 + Rs)   for transmitter sideAnd         n2 = RL/(RL1 + Rs)   for receiver sideQ1 = woL1/(RL1 + Rs)   Q2= woL2/(RL2 + RL)   But in this simulation Q1=Q2=QL1 and L2 can be any value: As efficiency is 96% it implies Rs=RL= 96 ohmRL1 and RL2 = 4 ohm = inductor coil resistance. If the size of the coil is defined (in your case), the inductance is fixed,too.L1=L2 in the above case because they are the same size.Did you measure the inductance L of the coil? It will be easier for me if you can provide the value for all the elements: C1, L1, C2, L2 and VoI have another question: Why the resistance of the coil is 4ohm if it is a single turn coil. (It is too large for a single turn coil).May I know why you need this kind of simulation? (What it is for?) Title: Re: magnetic induction communication system Post by: Taona on May 04, 2009, 12:38:50 am hie,i wish to implement a magnetic communication system project where i intend to use more than one antennafor improved channel capacity (like what is done in rf communications) hence I need to "see" wether it is possible.