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yuchenxi
China
7 Posts |
 Posted - Jul 30 2014 : 14:56:35
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Hello, I'm a new user.
I'm trying to replicate the results I have found in a paper published on an IEEE journal for the coil in Fig.1
[url]ht*p://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=04387341
The conductor is copper(conductivi 5.8108e7 Siemens/meter) with width 6.35mm and thickness 0.1778mm
Discretisation is : thickness divided into 10 filaments and width into 50 filaments.Frequencies are 63.86 MHz and 127.75 MHz.
The calculated inductances should be L#65288;63.86MHz#65289; = 66.72 mH and L#65288;127.75MHz#65289; = 79.75 mH. while my results is about 0.18mH at 63.86MHz.
This is my input file :
.units mm
.Default sigma=5.8e4 nhinc=10 nwinc=50
N1 x=0 y=48 z=0
N2 x=41.5 y=24 z=0
N3 x=41.5 y=-24 z=0
N4 x=0 y=-48 z=0
N5 x=-41.5 y=-24 z=0
N6 x=-41.5 y=24 z=0
N7 x=0 y=47.99 z=0
E1 N1 N2 w=6.35 h=0.1778
E2 N2 N3 w=6.35 h=0.1778
E3 N3 N4 w=6.35 h=0.1778
E4 N4 N5 w=6.35 h=0.1778
E5 N5 N6 w=6.35 h=0.1778
E6 N6 N7 w=6.35 h=0.1778
* Define ports
.external N1 N7
* Frequency range of interest
.freq fmin=63.86e6 fmax=63.86e6 ndec=1
* All input files must end ....
.end
Can someone help me out please?
thanks in advance.
Best regards |
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Enrico
550 Posts |
Posted - Aug 04 2014 : 19:30:59
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There are two issues here.
The first one is that the FastHenry file first line must NOT be the .units statement. The first line is ignored, so your units defaults to meters, giving you wrong results. The first line can safely be a comment (or a blank line, but definitely a title is better)
The second one, I'm afraid, is in the paper you cite. There is no way for an inductor so small to have an inductance of 66 mH. Running the simulation you get about 186 uH (micro Henry) that is a much more reasonable value. You can compare this value with a simple closed formula for a circular coil, as a sanity check, to get the feeling of the order of magnitude; or even with the flat spiral coil formulas in "Simple Accurate Expressions for Planar Spiral Inductances" by S. S. Mohan, M. M. Hershenson, S. P. Boyd, and T. H. Lee, IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 34, NO. 10, OCTOBER 1999 (you can even find online calculators for these formulas). I got about 220 uH with a crude approximation of a single-turn coil.
I suspect this apparently wrong result was not noticed since the paper deals in the end on how to minimize the mutual inductance, not on how to calculate or use the self inductance. I don't know if the error is the result of wrong coil dimensions, or of a wrong use of the Zc.mat results.
One last remark, you should use odd numbers for nhinc and nwinc, and definitely such an enormous discretization is not required. You should be happy also with much lower numbers, like nhinc=5 nwinc=11
(for precise numbers you should calculate the skin depth here, as indicated in FastHenry's user's manual)
Best Regards,
Enrico
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yuchenxi
China
7 Posts |
Posted - Aug 12 2014 : 16:42:17
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| I did some simulations with the paper you recommended to me,the results are well comply with the measured data. maybe there do is a mistake in the previous paper . thanks a lot. |
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yuchenxi
China
7 Posts |
Posted - Aug 12 2014 : 17:19:56
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By the way,recently#65292;i am studying the examples within the fasthenry.but there are some sentences and parameters that i really don't understand the meaning and usage.
here is a example
* a M5 line (26um wide, 1um thick) over Si substrate 8um below, sigma=2.6e7
* 430um thick substrate, sigma=1.5e4 1/(ohm*m)
* line length=1000um
.units uM
*
* Define substrate, sigma=1.5e4 1/(m*ohm)= 0.015 1/(um*ohm)
g1 x1 = -1500 y1 = -1500 z1 = 0
+ x2 = 1500 y2 = -1500 z2 = 0
+ x3 = 1500 y3 = 1500 z3 = 0
+ thick = 430 sigma= 0.015
*+ seg1 = 100 seg2 = 100
+ file=NONE
* under the trace
* under the trace
+ contact decay_rect (0,0,0,50,2000,13,3000,500,3000)
* the contacts
+ contact decay_rect (0,-1000,0,30,30,10,10,3000,3000)
+ contact decay_rect (0, 1000,0,30,30,10,10,3000,3000)
* the contacts
+ contact decay_rect (0,-1000,0,30,30,10,10,3000,3000)
+ contact decay_rect (0, 1000,0,30,30,10,10,3000,3000)
* +
+ nhinc = 3 rh=2
* nodes to reference later:
+ np1 (0,-1000,0)
+ np2 (0,1000,0)
*
* line width=26um
* thick h=1um sigma=2.6e7 1/(m*ohm)=26 1/(um*ohm)
*
NS1 x=0 y=-1000 z=223.5
NS2 x=0 y=1000 z=223.5
EM5 NS1 NS2 w=26 h=1 sigma=26 nwinc=4 nhinc=1
.equiv NS2 np2
.external NS1 np1
*
.freq fmin=3.3e8 fmax=3.3e8 ndec=1
.end
I don't know the meaning of this sentence," + contact decay_rect
(0,0,0,50,2000,13,3000,500,3000)",what's the decay_rect and what does the figures inside the bracket refer to?
besides,"+ nhinc = 3 rh=2" ,why there is nhinc and no nwinc?Is there a default value for nwinc? and what's the meaning of the parameter,rh,and the number,3.
thankes in advance.
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Enrico
550 Posts |
Posted - Aug 12 2014 : 21:51:57
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Please refer to FastHenry's user's guide. There are two documents in Acrobat reader format, both can be opened from the hyperlink in the main page of FastHenry2's embedded online help.
Best Regards,
Enrico
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yuchenxi
China
7 Posts |
Posted - Aug 13 2014 : 08:14:35
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| I can't find any information to these question and the online help option in windows version.The online help option is only available for the unix version? |
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Enrico
550 Posts |
Posted - Aug 13 2014 : 18:26:09
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I have uploaded a quick video on how to open the User's Manual, showing the main relevant sections answering your questions.
You can download the video from ht*p://w*w.fastfieldsolvers.com/Download/fasthenry2_user's_manuals.avi
I also uploaded the video to YouTube at ht*ps://w*w.youtube.com/watch?v=ZA_zCv4X11M&list=UUJ9zS6jZR1mZ37STNdFGXjw
(please replace the '*' with the proper character; h t t p and w w w are hidden for protection against spam linking)
Best Regards,
Enrico
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yuchenxi
China
7 Posts |
Posted - Aug 17 2014 : 03:22:54
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I have found it .Thanks a lot for your patient replies.
Best Regards,
Eric |
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hexagon self inductance
