# How to Design a Simple Antenna

```This article will show you how to build a monopoly for any use you see fit.
```

## Choose a frequency.

### Find out what frequency you want.

For Wi-Fi you are using 2.45GHz = 2,450,000,000Hz). This is needed because this determines the length of your antenna.

## Get a conductor.

### Choose a good conductor.

For the example we can use a copper wire and a piece of copper plating. Also you will need a co-axial cable (75 ohm is better than 50 ohm, for Wi-Fi 50 ohm is better than 75 ohm).

## Determine the wire length.

### Work out the length you need the wire to be.

This is done by using the frequency value from step 1 to find the wavelength of the signal. To do this you simply need to divide the speed of light (c = 299 792 458 m/s) by the frequency (f). In the case of 2.45GHz the wavelength is 12.236 centimeter (4.8 in). Usually monopole antennas are quarter-wavelength structures, so the length of the wire should be 12.236/4 = 3.0509cm

## Cut the wire.

### Cut the wire a little bigger than you need, about 6.5 centimeter (2.6 in) or so for a half-wave dipole antenna.

Cut about 3.2 centimeter (1.3 in) for a quarter-wave monopole. This way you can pare it back based on performance (and “tune” if needed) .

## Form a ground-plane.

### This is basically used to form a theoretical mirror image of the antenna.

Simply use the copper plate that you picked up earlier. It should be at least half a wavelength square.

## Drill a hole.

### Drill a hole in the center of the plate.

The whole should be just big enough for the co-axial cable to fit through.

## Pare the coaxial cable.

### Pare the coax cable to reveal its ground [outer conductor].

This can be pulled back to reveal the inside insulator.

## Feed the cable through.

### Push the cable through so that the start of outer insulation is flush with the hole.

The ground conductor is now above the ground-plane. Fold the ground conductor back and solder it to the copper ground plane.

## Solder the wire.

### Solder the copper wire to the signal conductor of the coax.

You now have an antenna.

## Tips

• The radiation pattern is null at the tip of the wire so make sure that you keep the antenna perpendicular to the source of the radio signals
• Make sure the wire is perpendicular to the ground plane
• The Antenna has a pretty much circular pattern when viewed from the top, so it should pick up your signal no matter where you decide to place it.

## Warnings

• If you short the GND and the signal wire you’ll be in trouble.
• Don’t let it get wet, as this frequency is not “friendly” to water.