1. Com3 2Q1617 Antenna Design Key design requirements
8/1/2018
Com3 2Q1617 Antenna Design
Key design requirements
Undertake the theoretical computations of shapes and geometries with clear preferably same scale illustrations
Provide the wire geometries input to NEC for all configurations in Excel table form; make sure intersections terminates exactly
You may have to configure curves and sheets with short sections of linear wire, compute the metric diameter of the 8AWG wire
A wire section should have at least 5 segments
Package report concisely, e.g. side by side comparisons of 3D and 2D plots, with 3 D antenna geometry, indicate gain F/B ratio and beam width for each pattern rather than one pattern per page
In addition to the profiles, make sure to include the wire diagrams and orient all diagrams so that it is clearly perceived by the reader, if necessary use more than one illustration for a particular configuration
Simulation is easy, the difficult part is the math of steps 1 and 2. Remember garbage in garbage out. There are also corrupted versions of NEC out there.
Hard copy final report, see separate PDF file for details
Soft copy to include all input data for the simulator, a user guide (notepad) if it will fit CD, an installation package.
X-axis propagation axis, Y-axis horizontal parallel to dipole elements, Z-axis vertical, center or origin at signal source.
JBC © 198 v A2,2

2. Com3 2Q1617 Antenna Design Design objective
Design an antenna for DTV GMA, using model X and Y as patterns
Driven horizontal dipole element + a parasitic mesh reflector
Corner reflector with angle of 90 degrees
Cylindrical reflector with parabolic cross section
Use AWG10 solid bare copper wire or aluminum tube as wire element.
Add a parasitic dipole director, optimize for gain by varying distance from driven element – thus you have to repeat the simulations at different distances
All groups to use the same power setting, etc…
Methodology
Simulate using NEC, choose best then fabricate one prototype
Design results
Radiation profiles 2D V/H 3D, antenna schematic, gain, beamwidth impedance; prototype with balun and interconnect to TV+
Comparative analysis: Compare of best of corner vs best of cylindrical
Prototype fabrication no metallic materials for boom, glue and support structures. Easy to disassemble for easy transport, structurally sound when assembled.
JBC © 198 v A2,2

3. 2Q1617 Model X
8/1/2018
Driven half wavelength dipole at these 2 distances 0.1 and 0.2 wavelength from common reflector.
Reflector is a cylindrical parabola, shorted at the two ends and with 5 horizontal elements to comprise the mesh, all wires electrically connected There are 7 wires, 2 of parabolic shapes. Set focus is 0.2 wavelengths
The width of the cylinder or lengths of the horizontal elements 105% of length of dipole. Horizontal elements equally spaced
The driven dipole should be in the plane of the mouth of the reflector at 0.2 wavelength
Provide one parasitic director with distance optimized for gain with a length of 95% of driven element
105%
JBC © 198 v A2,2

4. 8/1/2018
2Q1617 Model Y
Driven dipole at 0.1 and 0.2 wavelengths (same as model X) from center of 90 degrees corner reflector
90 degrees corner reflector shorted at the ends and comprised of 5 equally spaced vertical horizontal wire elements to comprise the mesh
The width of the reflector 105% of driven dipole, the height same as the diameter of the mouth of the parabola used in X
Provide one parasitic director with distance optimized for gain with a length of 95% of driven element