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<!DOCTYPE HTML SYSTEM "html.dtd">
<HTML>
<HEAD>
<TITLE>Examples of Structure Geometry Data </TITLE>
</HEAD>
<BODY>
<H2></H2>
<CENTER>
Examples of Structure Geometry Data
</CENTER>
<DL>
<DT><B><U>Rhombic Antenna - No Symmetry</U></B> </DT>
<DD>Structure: <A HREF="gifs/fig7.gif">Figure 7</A> </DD>
<DD><B>Geometry Data Cards</B> <PRE>GW 1 10 350. 0. 150. 0. 150. 150. .1
GW 2 10 0. 150. 150. 350. 0. 150. .1
GW 3 10 -350. 0. 150. 0. 150. 150. .1
GW 4 10 0. -150. 150. 350. 0. 150. .1
GS 0.30480
GE
</PRE>
</DD>
<DD>Number of Segments: 40 </DD>
<DD>Symmetry: None </DD>
<DD>These cards generate segment data for a rhombic antenna. The data are input
in dimension of feet and scalled to meters. In the figure, numbers near the
structure represent segment numbers and circuled numbers represent tag numbers
</DD>
</DL>
<DL>
<DT><B><U>Rhombic Antenna - Plane Symmetry, 2 Planes</U></B> </DT>
<DD>Structure: <A HREF="gifs/fig8.gif">Figure 8</A> </DD>
<DD><B>Geometry Data Cards</B> <PRE>GW 1 10 -350. 0. 150. 0. 150. 150. .1
GX 1 110
GS 0.30480
GE
</PRE>
</DD>
<DD>Number of Segments: 40 </DD>
<DD>Symmetry: Two planes </DD>
<DD>These cards generate the same structure as the previous set allthough the
segment numbering is altered. By making use of two planes of symmetry, these
data will require storage of only a 10 by 40 interaction matrix. If segments 21
and 31 are to be loaded as the termination of the antenna, then symmetry about
the YZ plane cannot be used. The following cards will result in symmetry about
only the xZ plane being used in the solution; thus, allowing segments on one
end of the antenna to be loaded. </DD>
</DL>
<DL>
<DT><B><U>Rhombic Antenna - Plane Symmetry, 1 Plane</U></B> </DT>
<DD>Structure: <A HREF="gifs/fig9.gif">Figure 9</A> </DD>
<DD><B>Geometry Data Cards</B> <PRE>GW 1 10 -350. 0. 150. 0. 150. 150. .1
GX 1 100
GX 2 010
GS 0.30480
GE
</PRE>
</DD>
<DD>Number of Segments: 40 </DD>
<DD>Symmetry: One plane </DD>
<DD>Segments 1 through 20 of this structure are in the first symmetric section.
Hence, segments 11 and 31 can be loaded without loading segments 1 and 21
(loading segments in symmetric structures is discussed in the section covering
the LD card). These data will cause storage of a 20 by 40 interaction matrix.
</DD>
</DL>
<DL>
<DT><B><U>Two Coaxial Rings</U></B> </DT>
<DD>Structure: <A HREF="gifs/fig10.gif">Figure 10</A> </DD>
<DD><B>Geometry Data Cards</B> <PRE>GW 1 1 1.0 0. 0. 0.70711 0.70711 0. .001
GW 2 1 2.0 0. 0. 0.76536 1.84776 0. .001
GW 2 1 0.76536 1.84776 0. 1.41421 1.41421 0. .001
GR 8
GM 90.0 0. 0. 0. 0. 2.0
GE
</PRE>
</DD>
<DD>Number of Segments: 24 </DD>
<DD>Symmetry: 8 section cylindrical symmetry </DD>
<DD>The first 45 degree section of the two rings is generated by the first
three GW cards. This section is then rotated about the X-axis to complete the
structure. The rings are then rotated about the X-axis and elevated to produce
the structure shown. Since no tag increment is specified on the GR card. All
segments on the first ring have tags of 1 and all segments on the second ring
have tags of 2. Because of symmetry, these data will require storage of only a
3 by 24 interaction matrix. IF a 1 were punched in column 5 of the GE card,
however, wymmetry would be destroyed by the interaction with the ground,
requiring stroage of a 24 by 24 matrix </DD>
</DL>
<DL>
<DT><B><U>Linear Antenna over a Wire Grid Plate</U></B> </DT>
<DD>Structure: <A HREF="gifs/fig11.gif">Figure 11</A> </DD>
<DD><B>Geometry Data Cards</B> <PRE>GW 1 0. 0. 0. 0.1 0. 0. .001
GW 1 0. 0. 0. 0. 0.1 0. .001
GM 2 0. 0. 0. 0. 0.1 0.
GW 1 0. 0.3 0.0 0.1 0.3 0. .001
GM 4 0. 0. 0. 0.1 0. 0.
GW 3 0.5 0. 0. 0.5 0.3 0. .001
GM 0. 0. 0. -0.25 -0.15 0.
GW 1 5 -0.25 0. 0.15 0.25 0. 0.15 .001
GE
</PRE>
</DD>
<DD>Number of Segments: 43 </DD>
<DD>Symmetry: None </DD>
<DD>The first 6 cards generate data for the wire grid plate, with the lower
left-handcorner at the coordinate origin, by using the GM card to reproduce
sections of the structure. The GM card is then used to move the center of the
plate to the origin. Finally, a wire is generated 0.15 meters above the plate
with a tag of 1. </DD>
</DL>
<DL>
<DT><B><U>Cylinder with Attached Wwires</U></B> </DT>
<DD>Structure: <A HREF="gifs/fig12.gif">Figure 12</A> </DD>
<DD><B>Geometry Data Cards</B> <PRE>SP 10. 0. 7.3333 0. 0. 38.4
SP 10. 0. 0. 0. 0. 38.4
SP 10. 0. 7.3333 0. 0. 38.4
GM 1 0. 0. 30.
SP 6.89 0. 11. 90. 0. 44.89
SP 6.89 0. 11. 90. 0. 44.89
GR 6
SP 0. 0. 11. 90. 0. 44.89
SP 0. 0. 11. 90. 0. 44.89
GW 4 0. 0. 11. 0. 0. 23. .1
GW 5 10. 0. 0. 27.6 0. 0. .2
GS .01
GE
</PRE>
</DD>
<DD>Number of Segments: 9 </DD>
<DD>Number of Patches: 56 </DD>
<DD>Symmetry: None </DD>
<DD>The cylinder is generated by first specifing three patches in a column
centered on the X asis as shown in <A HREF="gifs/fig12.gif">figure 12(a)</A>. A
<A HREF="cards/gm.html">GM</A> card is then used to produce a second column of
patches rotated about the Z axis by 30 eegrees. A patch is added to the top and
another to the bottom to form parts of the end surfaces. The model at this
point is shown in <A HREF="gifs/fig12.gif">figure 12(b)</A>. next a
<A HREF="cards/gr.html">GR</A> card is used to rotate this section of patches
about the Z axis to form a total of six similar sections, including the
original. A patch is then added to the center of the top and another to the
bottom to from the complete cylinder shown in <A HREF="gifs/fig12.gif">figure
12(c)</A>. Finally, two <A HREF="cards/gw.html">GW</A> cards are used to add
wires connecting to the top and side of the cylinder. The patches to which the
wires are connected are devided into four smaller patches as shown in
<A HREF="gifs/fig12.gif">figure 12(d)</A>. Although patch shape is not input to
the program, square patches are assumed at the base of a connected wire when
integrated over the surface current. Hence, a more accurate representation of
the model would be as shown in <A HREF="gifs/fig13.gif">figure 13</A>, where
the patches to which wires connect are square with equal areas maintained for
all patches (before subdivision). </DD>
</DL>
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