Input to ACES CEM Software Sourcebook

CODE: MININEC Professional for Windows (Ver. 1.5)
PUBLISHER/DISTRIBUTER: EM Scientific, Inc.
AUTHORS: J.W. Rockway and J.C. Logan
CATEGORY: Method of moments; user interface (pre- and post processing)
PURPOSE:
        Design and analysis of wire antennas and wire grid structures in free space
and over perfectly conducting and finite ground.
LANGUAGE:
        Computational engines are compiled in Microsoft FORTRAN. User interface is
compiled in Visual BASIC.
COMPUTERS:
        IBM PC or compatible with 386 or 486 processor and minimum 2 megabytes
memory. Requires 3.5 inch disk drive and mouse recommended. Requires Windows
3.0 or higher (including Windows 95 and Windows NT).
AVAILABILITY:
Price: $390.00 including shipping. Discount available for bulk orders.
Mail order from:
EM Scientific, Inc. (702) 888-9449
2533 N. Carson Street, Suite 2107 FAX: 883-2384
Carson City, NV 89706 EMAIL: 76111.3171_at_compuserve.com
        Payment in U.S. Dollars is required. Check or credit card (Visa or
Mastercard) accepted. Include card number, expiration date, signature and
telephone. Purchase orders from corporate customers are acceptable. Terms
are Net 30 for domestic orders and Net 60 for overseas orders. A substantial
late payment fee will be imposed on unpaid balances after the due date.
DESCRIPTION:
        MININEC Professional solves an electric field formulation for the currents
on electrically thin wires using a Galerkin procedure with triangular basis
functions. Radiation patterns, near fields, charge distribution, impedance
and other useful parameters are computed from the current solution. The user
interface provides graphical displays in 3-D of geometry, current and charge
distributions, and radiation patterns. Other graphical output includes
linear and logarithmic plots as well as polar plots and smith charts.
Limitations and Approximations:
        MININEC Professional is dimensioned to 1000 wires and 2000 unknowns. The
actual large problem computational capability depends on the internal memory
available on the PC in use. Wires and segmentation should conform to the
usual thin wire criteria. The short segment limit is determined by machine
precision. The smallest loop is 10E-4 wavelengths in circumference.
LIMITATIONS AND APPROXIMATIONS:
        The usual thin wire approximations are used. The currents are assumed to
flow axially with no circumferential component. Radii should be less than
0.01 wavelengths, but good results have been obtained to 0.03 wavelengths.
 The segment length to radius ratio should be less than or equal to 8, but
good results as low as 2 may be obtained. Segment length should be less than
or equal to 0.1 wavelengths for best results. Good results have been shown
to a low frequency of 3E-13 MHz. Segment length ratio on wires at wire
junctions should be from 1 to 5. Radius ratio at wire junctions should be
less than 10 for best results, but good results have been shown with a ratio
up to 100.
REPRESENTATIVE GEOMETRIES/PROBLEMS:
        MININEC Professional can be used to design and analyze the performance of
dipoles, monopoles including folded monopoles, yagis, log periodics, loops
(circular and square), helix, spirals many others. Wire grids can be used
to model antennas mounted on small structures and vehicles.
STORAGE AND TIMING FOR REPRESENTATIVE GEOMETRIES:
        MININEC Professional requires minimum of 2 megabytes memory. With
approximately 8 megabytes of internal memory, a problem with 700 unknowns can
be solved. With 20 megabytes of internal memory, a problem of approximately
1400 unknowns can be solved. A 700 unknown dipole can be solved in
approximately 5 minutes on a PC running at 75 MHz. MININEC Professional is
dimensioned for 1000 wires and 2000 unknowns. The large problem
computational capability depends on the internal memory available.
        Recently on NEC-LIST, a couple of antenna problems have been proposed for
the
timing of NEC calculations. These two problems were also run using MININEC
Professional. These calculations were made using an Intel Pentium 133-MHz
with 256 KB of cache.
        The first problem was proposed by Larry Laitinen. The problem is a 299
segment dipole over perfect ground. The NEC data set is the following:
CM
CE
GW 1,299,-139.,0, 6.,+139.,0, 6., .001,
GE 0,
GN 1,
FR 0,0,0,0, 0.54,
EX 0, 1,150,0,1., 0.,
RP 1, 1, 1,0000, 1.5, 0., 0., 0., 1000.,
EN
MININEC Professional computed this problem in 9 seconds using the same 299
unknowns. This is compared to NEC calculation of the 22 seconds on an Intel
Pentium 120-MHz.
        The second problem is attributed to John Boyer. The NEC data set is the
following:
CM
CE
GW33,20,.0,-.025,.28,.0,-.025,-.89,.004,
GM1,2,0.,0.,0.,0.,.025,0.,33.,
GM1,5,0.,0.,0.,-.025,0.,0.,35.,
GM5,1,0.,0.,0.,.0,-.05,0.,36.,
GW49,25,.14,0.,-.19,.14,0.,.19,0.014,
GM1,1,0.,0.,0.,0.,0.,-.61,49.,
GM0,0,0.,0.,0.,.17,0.,0.,0.,
GW100,12,0.,-.75,.39,0.,-.75,-1.,.004
GM1,59,0.,0.,0.,0.,.025,0.,100.,
GE0,0,0.,
EX0,49,13,00,1.,0.,
EX0,50,13,00,1.,0.,
FR0,1,0,0,500.,0.,0.,
RP0,1,359,1010,90.,0.,0.,1.,0.,0.,
EN
This is a problem with 75 antennas. The problem requires 1030 unknowns to
be calculated. Ray Anderson reported times for a Sun UltraSparc2 and a SUN
SparcServer 1000. The Sun UltraSparc2 (dual 167 MHz UltraSparc2 processors)
had a fastest time of approximately 530 seconds. MININEC Professional
computed this problem in 234 seconds on the Intel 133-MHz.
EXTENT AND KINDS OF VALIDATION
        The book, "MININEC Professional for Windows", which accompanies the
software, provides a description of the software and presents the theory with
relevant examples and validation data. Comparison is made to measurements
and computations published by R.W.P. King. Extensive comparison is made to
the performance of NEC4. Validation problems includes monopoles, dipoles,
loops, yagis, tee antennas and others.
ADDITIONAL INFORMATION
        For more information on MININEC Professional and future developments, please
see the EM Scientific, Inc. Web page at www.sierra.net/emsci.
REFERENCES
        "MININEC Professional for Windows", by J.W. Rockway and J.C. Logan, EM
Scientific, Inc., Carson City, Nevada, March 1995, ISBN: 1-88743-00-9,
Library of Congress Catalog Card Number 95-060536.
Received on Sat May 25 1996 - 18:28:00 EDT