Telecommunications

JBCardenas © 1982

Com3 3Q1415 Antenna Design

JBC © 198 v A2,2

Additional data is in a separately provided Excel file.

Key design requirements1. Provide the computations of shapes and geometries with

matching illustrations2. Provide the final wire geometries input to NEC for all

configurations3. You may have to configure curves and spirals with short

sections of linear wire, compute the metric diameter of the 10AWG wire

4. A linear wire section should have at least 3 segments5. In addition to the design specs, you have to configure four

more designs with an optional 5th one for comparison purposes6. Package report concisely, e.g. side by side comparisons of 3D

and 2D plots, indicate gain for each pattern7. 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

8. Groups will either do design A or design B, at least 5 different antennas each group; after grouping any late comers shall do design C

9. Simulation is easy, the difficult part is the math of steps 1 and 2. GIGO.

Telecommunications

JBCardenas © 1982

Com3 3Q1415 A

JBC © 198 v A2,2

Use NEC: Spherical Parabolic mesh parasitic reflector comprised of six wire elements 3 circles and 3 identical parabolic curved sections at 60 degrees separation, one of which is parallel to ground; make sure everything is electrically connected. Use 10AWG bare solid copper wire

Design for center frequency of 479 MHz, small bandwidth: log-periodic (equiangular) spiral dipole placed at the focus or center of parabolic reflector; inner radius of spiral = to diameter smallest circle , outer radius approx = to diameter middle circle, biggest circle same plane as driven spiral. Number of turns approx 1.5, flare rate approx 0.22.

Compare performance at given frequency, e.g. gain, beamwidth vs spiral w/o reflector, vs Yagi with a parasitic director same distance as focal length, vs Yagi with reflector 10% wavelength, and vs design with isotropic point source. Optional: compare also with solid parabolic reflector

At least five different configurations, see additional Excel file data

Telecommunications

JBCardenas © 1982

Com3 3Q1415 B

JBC © 198 v A2,2

Use NEC: one driven quad element, 6 parasitic quad elements electrically isolated from each other. Planes of two parasitic quads parallel to plane of driven element at distances 0.1 lambda, opposite sides of driven element. Four other reflector quads surrounds the driven element at 60 degree angles; center of these quads on the same plane as driven element. All 5 reflector quads of same size and shape; distance between nearest sides of reflectors 0.01 l. Bottom side feed.

Design for 479 MHz: Use 10AWG bare solid copper wire. Perimeter lengths of quad: driven 2, director 1.8 and reflectors 2.2 l.

60

Compare performance, e.g. gain, beamwidth vs Yagi with dipole parasitic director and parasitic reflector 0.1 l from horizontal dipole driven element, vs same design but replacing driven with a turn stile array, vs same design but replace all with hexagon (with 2 sides parallel to ground), and vs same design but with turnstile dipoles for driven element and a cross (parallel to turnstile) for director. Optional: compare also with solid plate quad reflector elements

At least five different configurations, see Excel file for additional data

Telecommunications

JBCardenas © 1982

Com3 3Q1415 Latecomers after Grouping

JBC © 198 v A2,2

Same as design A but use a hyperbolic reflector.

Compare performance at given frequency, e.g. gain, beamwidth v.s.

1. Yagi with a parasitic reflector same distance as focal length2. Yagi with reflector 10% wavelength3. Same design C but with isotropic point source4. Same design C but with turnstile source5. Optional: same design C but with solid metal sheet hyperbolic

reflector

At least five different configurations