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 filename


     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 documen-
     tation - 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  graph-
     ics  program),  for microstrip couplers. Hence if the dimen-
     sions of a coupler are known the odd mode, even  mode,  dif-
     ferential  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

     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 per-
     mittivity 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  copy-
     right 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

     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 pos-
     sible 16777216 colours can be defined precisely by the stat-
     ing the exact amount of red, green and blue, as in:

     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 create_bmp_for_rect_cen_in_rect.

     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 purposes)


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

     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  >
     % atlc ex1.bmp

     In this second example, an inner of 15.0 mm x 0.5 mm is sur-
     rounded  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  accu-
     racy, 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  permittivi-
     ties 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
     In the sixth and final example, the -v  option  is  used  to
     print     some     extra     data     to     stderr     from


     atlc(1)                       create_bmp_for_circ_in_circ(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

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