An advantage inherent to patch antennas is the ability to have polarization diversity.

A single patch antenna provides a maximum directive gain of around 6-9 dBi.

A simple patch antenna of this type radiates a linearly polarized wave.

Since the 1980s, versions for use at microwave frequencies have been made with patch antenna elements mounted in front of a metal surface.

The patch antenna consists mainly of a square conductor mounted over a groundplane.

Patch antennas are simple to fabricate and easy to modify and customize.

A typical radiation pattern for a linearly-polarized 900-MHz patch antenna is shown below.

It is also possible to fabricate patch antennas that radiate circularly-polarized waves.

This unique property allows patch antennas to be used in many types of communications links that may have varied requirements.

For implanted applications, dipole, loop and patch antennas can all be used within this band.

The patch antennas may also be placed on stands or a finish gantry pointing towards the oncoming athlete.

The gain of a rectangular microstrip patch antenna with air dielectric can be very roughly estimated as follows.

The patch antenna that will be used when the service is up and running will be two inches square, about the size of a business card.

And then there is the patch antenna, one of the simplest, which looks like a flat piece of metal that projects the signal from its plane.

The fractional bandwidth of a patch antenna is linear in the height of the antenna.

A patch antenna is usually constructed on a dielectric substrate, using the same materials and lithography processes used to make printed circuit boards.

The impedance bandwidth of a patch antenna is strongly influenced by the spacing between the patch and the ground plane.

Patch antennas utilized by industry often use ground planes which are only modestly larger than the patch, which also alters their performance.

Patch antenna - another antenna for GPS applications.

The rectangular patch antenna is approximately a one-half wavelength long section of rectangular microstrip transmission line.

They are composed of an array of many identical small flat antenna elements, such as dipole, horn, or patch antennas, covering the surface.

If the circular patch antenna is perturbed into an ellipse and fed properly it can produce circularly polarized electromagnetic waves.

For UHF systems the antennas consist of patch antennas that are protected in a matting system.

A microstrip UHF patch antenna will be used for communication with the MSE.

Measurements of this early prototype hardware, built with super sized pixels about 6 mm wide, have demonstrated tunable patch antenna structures operating at microwave frequencies.