How to build a parabolic reflector

Written by adam quinn
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How to build a parabolic reflector
Mount your Wi-Fi antenna at the parabolic reflector's focal point and boost the signal strength. (Comstock/Comstock/Getty Images)

If you'd like to boost the strength of your Wi-Fi signal, you can build a parabolic reflector for your omnidirectional wireless antenna. A parabolic reflector focuses incoming signals to its focal point, which lays in space, in front of the curved material. The reflector concentrates outgoing signals, that originate from the focal point, in a direction perpendicular to the curve. When a receiving element and transmitting source, such as a Wi-Fi antenna, is positioned at a reflector's focal point, the signal is boosted in the particular direction that the reflector is pointed. Graph the parabolic curve, and build a metal parabolic reflector for your Wi-Fi antenna.

Skill level:

Things you need

  • Graph paper, 4 squares per inch
  • Pencil
  • 2 pieces of thick cardboard, 5 inches square
  • Cutting board
  • Utility knife
  • Ruler
  • Aluminium sheet metal, 12 inches square
  • Tin snips
  • Household adhesive cement
  • Work gloves

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  1. 1

    Mark a centre point on the graph. This location will be the vertex of the parabolic curve. Count eight squares up from the vertex and mark the curve's focal point.

  2. 2

    Plot a parabolic curve with a 2-inch focal point on the graph paper. Count four squares to the right of the vertex and half a square up. Mark this point. This point can be represented as (4, 1/2), where the first number is the horizontal coordinate and the second number is the vertical coordinate. Mark a second point six squares from the right of the vertex and one square up, or at the coordinate (6, 1). Mark additional points at (8, 2), (10, 3), (12, 4 1/2), (14, 6) and (16, 8).

  3. 3

    Perform this procedure to mark points on the left side of the vertex, mirroring the points on the right side. Mark the first point, four squares from the left of the vertex and half a square up. This point can be represented as (-4, 1/2). Mark additional points at (-6, 1), (-8, 2), (-10, 3), (-12, 4 1/2), (-14, 6) and (-16, 8).

  4. 4

    Connect the points together to form a bowl-shaped curve that opens upward. Connect the points with slightly curved lines to form a smoothly drawn parabola.


  1. 1

    Lay the graph paper atop the cardboard square. Center the parabolic curve over the cardboard. Poke a hole, using a pencil, through the paper, and into the cardboard at the focal point mark. Trace the curve using a pencil. Press the pencil firmly into the graph paper to leave an indentation of the curve in the cardboard below it.

  2. 2

    Place a square of cardboard on a cutting board. Poke the pencil completely through cardboard at the focal point mark. Cut out the curve indentation in the cardboard using a utility knife. Cut the curve from the second square of cardboard with a utility knife, using the first cardboard curve as a template. Poke an identical focal point hole through the second piece of cardboard.

  3. 3

    Measure the height of your Wi-Fi antenna. Measure and cut the sheet metal square to a width equal to the antenna's height.

  4. 4

    Position one end of the sheet metal rectangle at one end of the cardboard curve. Bend the sheet metal around the curve, and mark the location of curve's opposite end on the metal. Cut the sheet metal to this length using tin snips.

  5. 5

    Expand the focal point holes in the cardboard curves to fit the thickness of your Wi-Fi antenna.

  6. 6

    Bend the sheet metal around the cardboard curves, and fasten the metal to the curves using an adhesive cement. The cardboard curves should be equally spaced along the height of the sheet metal.

  7. 7

    Slide the parabolic reflector over your Wi-Fi antenna. Position the reflector opposite the signal source direction.

Tips and warnings

  • Build a second parabolic reflector for your dual-antenna Wi-Fi router.
  • Wear work gloves to protect your hands from the sharp metal edges.

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