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Why does an example on comsol website use 13W power for a cellphone?
Posted Mar 7, 2017, 11:43 p.m. EST RF & Microwave Engineering, Heat Transfer & Phase Change 3 Replies
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Hello all,
I'm new to comsol, i have been learning it by internet, i have started solving some examples available on comsol website. The link of the example is mentioned below-
www.comsol.com/model/absorbed-radiation-sar-in-the-human-brain-2190
and i have also attached the pdf file for this example. One thing that is bugging me is in the lumped port section (page no.15 of pdf), they put v= 45.5 and Z= 75 ohm that means p= 13W, but the maximum power that a cell phone can radiate is 2W so why are they using 13W?
Thanks in advance!
I'm new to comsol, i have been learning it by internet, i have started solving some examples available on comsol website. The link of the example is mentioned below-
www.comsol.com/model/absorbed-radiation-sar-in-the-human-brain-2190
and i have also attached the pdf file for this example. One thing that is bugging me is in the lumped port section (page no.15 of pdf), they put v= 45.5 and Z= 75 ohm that means p= 13W, but the maximum power that a cell phone can radiate is 2W so why are they using 13W?
Thanks in advance!
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3 Replies Last Post Apr 5, 2017, 2:46 a.m. EDT
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Posted:
7 years ago
That is a good point but the antenna is rather poorly matched so the radiated power is only about 0.54W which is not unrealistic. The latter can be seen by postprocessing the lumped port power, i.e. under
Results/Derived Values
add a Global Evaluation node and evaluate the expression "emw.Pport_1"
The focus in the example is meant to be on the calculation of the specific absorption rate in the brain rather than on the detailed and realistic modeling of a cellphone antenna.
--
Magnus
Results/Derived Values
add a Global Evaluation node and evaluate the expression "emw.Pport_1"
The focus in the example is meant to be on the calculation of the specific absorption rate in the brain rather than on the detailed and realistic modeling of a cellphone antenna.
--
Magnus
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Posted:
7 years ago
Thanks for your reply magnus,
I can understand it is just an example and it is mainly focused on SAR and temperature distribution calculation. But is there any specific reason of choosing 13W? is this the condition of over exposure?
secondly, i use the global matrix evaluation, put that expression and run the simulation i cannot understand what is it showing?
Thanks!
I can understand it is just an example and it is mainly focused on SAR and temperature distribution calculation. But is there any specific reason of choosing 13W? is this the condition of over exposure?
secondly, i use the global matrix evaluation, put that expression and run the simulation i cannot understand what is it showing?
Thanks!
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Posted:
7 years ago
The port voltage level was chosen in order to give a reasonable/realistic SAR distribution and temperature increase.
When it comes to the global matrix evaluation node, that is only applicable after you have performed a port sweep over several ports so that you have an S-parameter matrix rather than the degenerate scalar case with just S11. If you want to display S11 for a single port system, use a Global Evaluation node.
--
Magnus
When it comes to the global matrix evaluation node, that is only applicable after you have performed a port sweep over several ports so that you have an S-parameter matrix rather than the degenerate scalar case with just S11. If you want to display S11 for a single port system, use a Global Evaluation node.
--
Magnus