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       create_bmp_for_microstrip_coupler  -  bitmap  generator  for microstrip
       coupler (part of atlc)


       create_bmp_for_microstrip_coupler [-b bmp_size] [-v] w s g h t Er1  Er2


       This  man  page is not a complete set of documentation - the complexity
       of the atlc project makes man pages not an ideal way  to  document  it,
       although  out  of  completeness,  man  pages  are  produced.   The best
       documentation that was current at the time  the  version  was  produced
       should be found on your hard drive, usually at
       although  it  might  be elsewhere if your system administrator chose to
       install the package elsewhere. Sometimes, errors are corrected  in  the
       documentation  and  placed at before a new
       release of atlc is released.  Please, if you notice a problem with  the
       documentation - even spelling errors and typos, please let me know.


       create_bmp_for_microstrip_coupler  is a pre-processor for atlc, part of
       atlc properties of a two and three  conductor  electrical  transmission
       line      of      arbitrary      cross     section.     The     program
       create_bmp_for_microstrip_coupler is used as a fast way  of  generating
       bitmaps  (there  is  no need to use a graphics program), for microstrip
       couplers. Hence if the dimensions of a coupler are known the odd  mode,
       even  mode,  differential mode and common mode impedances can be found.
       If  you  know  what  impedances  you  require  and  want  to  find  the
       dimentions,   then  use  find_optimal_dimensions_for_microstrip_coupler
       instead.       This        makes        repeated        calls        to
       create_bmp_for_microstrip_coupler.  The structure for which bitmaps are
       generated by create_bmp_for_microstrip_coupler is shown below.

       G                                                     G  |
       G                                                     G  |
       G                                                     G  |
       G                                                     G  |
       G                                                     G  |
       G                                                     G  |
       G |                                                   G  |
       G |                                                   G  |
       G |                                                   G  H
       G v       <--g--><--w--><---s---><--w--><--g-->       G  |
       GGGGGGGGGG       ccccccc         ccccccc       GGGGGGGG  |
       GGGGGGGGGG.......ccccccc.........ccccccc.......GGGGGGGG  |
       G.^.....................................^.............G  |
       G.|.....................................|.............G  |
       G.|t.Dielectric, permittivity=Er2.......h.............G  |
       G.|...(3.7 for FR4 PCB).................|.............G  |
       G.......................................V.............G  |

       The parameters ’W’ and ’H’ and the inner  dimensions  of  the  a  metal
       enclosure.   These  will  generall  be  quite  large  compared  to  the
       dimensions of the the PC - the diagram above is not to scale.  The  gap
       between the two coupled lines is s, the width of the coupled lines is w
       and the spacing  between  the  edges  of  the  coupled  lines  and  the
       groundplane  on the top is g. Often, the upper groundplane is not close
       to the coupled lines,  in  which  case  g  will  be  quite  large.  The
       thickness  of  the dielectic is h. Note that he is just the dielectric,
       and does not include the thichkness of the copper on  the  double-sided
       PCB.  The  thickness  of copper on the top layer is t. It is immaterial
       what the thickkness of the lower layer is.  The  relative  permittivity
       above  the  dielectric  is normally 1, but the relative permittivity of
       the dielectric material will need to be either pre-defined  or  defined
       on   the  command  lines.  See  the  section  colours  below  for  more
       information on dielectrics.

       The bitmap is printed to the file specified as the last argument

       The bitmaps produced by  create_bmp_for_microstrip_coupler  are  24-bit
       bit colour bitmaps, as are required by atlc.

       The permittivities of the bitmap, set by ’Er1’ and ’Er2’, determine the
       colours in the bitmap. If Er1 or Er2 is 1.0, 1.0006,  2.1,  2.2,  2.33,
       2.5,  3.3,  3.335, 3.7, 4.8, 10.2 or 100, then the colour corresponding
       to that permittivity will be set according to the  colours  defined  in
       COLOURS below. If Er1 is not one of those permittivities, the region of
       permittivity Er1 will be set to the colour 0xCAFF00. If Er2 is not  one
       of those values, then the region of the image will be set to the colour
       0xAC82AC. The program atlc does not know what these  two  permittivites
       are,  so  they atlc, must be told with the comand line option -d, as in
       example 4 below.


       -C Causes  create_bmp_for_microstrip_coupler  to  print  copyright  and
       licensing information.  -b bitmapsize
       is  used  to  set  the size of the bitmap, and so the accuracy to which
       atlc is able to  calculate  the  transmission  line’s  properties.  The
       default  value  for ’bitmapsize’ is normally 4, although this is set at
       compile time. The value can be set anywhere from 1 to 15, but more than
       8 is probably not sensible.

       Causes  create_bmp_for_microstrip_coupler to print some data to stderr.
       Note, nothing extra goes to standard output, as that is expected to  be
       redirected to a bitmap file.


       The 24-bit bitmaps that atlc expects, have 8 bits assigned to represent
       the amount of red, 8 for blue and 8 for  green.  Hence  there  are  256
       levels  of  red, green and blue, making a total of 256*256*256=16777216
       colours.  Every one of the possible 16777216  colours  can  be  defined
       precisely  by  the  stating the exact amount of red, green and blue, as

       red         = 255,000,000 or 0xff0000
       green       = 000,255,000 or 0x00ff00
       blue        = 000,000,255 or 0x0000ff
       black       = 000,000,000 or 0x000000
       white       = 255,255,255 or 0xffffff
       Brown       = 255,000,255 or 0xff00ff
       gray        = 142,142,142 or 0x8e8e8e

       Some colours, such as pink, turquoise, sandy, brown, gray etc may  mean
       slightly  different  things  to  different  people. This is not so with
       atlc, as the program expects the colours below to be EXACTLY defined as
       given. Whether you feel the colour is sandy or yellow is up to you, but
       if you use it in your bitmap, then it  either  needs  to  be  a  colour
       recognised  by  atlc,  or you must define it with a command line option
       (see OPTIONS and example 5 below).
       red    = 255,000,000 or 0xFF0000 is the live conductor.
       green  = 000,255,000 or 0x00FF00 is the grounded conductor.
       blue   = 000,000,000 or 0x0000FF is the negative conductor

       All bitmaps must have the live (red) and  grounded  (green)  conductor.
       The  blue  conductor is not currently supported, but it will be used to
       indicate a negative conductor, which will be needed if/when the program
       gets extended to analyse directional couplers.

       The following dielectrics are recognised by atlc and so are produced by

       white     255,255,255 or 0xFFFFFF as Er=1.0    (vacuum)
       pink      255,202,202 or 0xFFCACA as Er=1.0006 (air)
       L. blue   130,052,255 or 0x8235EF as Er=2.1    (PTFE)
       Mid gray  142,242,142 or 0x8E8E8E as Er=2.2    (duroid 5880)
       mauve     255.000,255 or 0xFF00FF as Er=2.33  (polyethylene)
       yellow    255,255,000 or 0xFFFF00 as Er=2.5    (polystyrene)
       sandy     239,203,027 or 0xEFCC1A as Er=3.3    (PVC)
       brown     188,127,096 or 0xBC7F60 as Er=3.335  (epoxy resin)
       Turquoise 026,239,179 or 0x1AEFB3 as Er=4.8    (glass PCB)
       Dark gray 142,142,142 or 0x696969 as Er=6.15   (duroid 6006)
       L. gray   240,240,240 or 0xDCDCDC as Er=10.2  (duroid 6010)
       D.  orange  213,160,067  or  0xD5A04D  as  Er=100.0  (mainly  for  test


       Here      are      a     few     examples     of     the     use     of
       create_bmp_for_microstrip_coupler. Again, see the html documentation in
       atlc-X.Y.Z/docs/html-docs/index.html for more examples.

       In  the first example, there is just an air dielectric, so Er1=Er2=1.0.
       The inner of 1x1 inches (or mm, miles etc) is placed  centrally  in  an
       outer with dimensions 3 x 3 inches.

       The  exact  place where the dielectric starts (a) and its width (d) are
       unimportant, but they must still be entered.

       % create_bmp_for_microstrip_coupler 3 3 1 1 1 1 1 1 > ex1.bmp
       % atlc ex1.bmp

       In this second example, an inner of 15.0 mm x 0.5 mm is  surrounded  by
       an  outer  with  internal  dimensions  of  61.5  x  20.1 mm. There is a
       material with permittivity 2.1 (Er of PTFE) below the inner  conductor.
       The  output  from  create_bmp_for_microstrip_coupler  is sent to a file
       ex1.bmp, which is then processed by atlc

       % create_bmp_for_microstrip_coupler 61.5 20.1 5 22 0.5 50 15 5 1.0  2.1
       > ex2.bmp
       % atlc ex2.bmp

       In  example  3,  the  bitmap  is made larger, to increase accuracy, but
       otherwise   this   is   identical   to   the   second    example.     %
       create_bmp_for_microstrip_coupler  -b7  61.5  20.1 5 22 0.5 50 15 5 1.0
       2.1 > ex3.bmp
       % atlc ex3.bmp

       In the fourth example, materials with permittivites 2.78 and  7.89  are
       used.    While    there    is    no    change    in    how    to    use
       create_bmp_for_microstrip_coupler, since these permittivities  are  not
       known,     we     must     tell     atlc     what    they    are.     %
       create_bmp_for_microstrip_coupler 61 20 1 4 22 0.5 50 15 5 2.78 7.89  >
       ex5.bmp  %  atlc -d CAFF00=2.78 -d AC82AC=7.89 ex5.bmp In the sixth and
       final example, the -v option is used to print some extra data to stderr
       from create_bmp_for_microstrip_coupler.


       atlc(1)  create_bmp_for_circ_in_circ(1)  create_bmp_for_circ_in_rect(1)
       create_bmp_for_rect_in_circ(1)      create_bmp_for_stripline_coupler(1)
       create_bmp_for_symmetrical_stripline(1)               design_coupler(1)
       find_optimal_dimensions_for_microstrip_coupler(1) readbin(1)                - Home page       - Download area
       atlc-X.Y.Z/docs/html-docs/index.html       - HTML docs
       atlc-X.Y.Z/docs/qex-december-1996/atlc.pdf - theory paper
       atlc-X.Y.Z/examples                        - examples

Dr. David Kirkby           atlc-4.4.2 10thcreate2bmp_for_microstrip_coupler(1)