Antennas for low power applications

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Doc ID 023812 Rev 1

Figure 19.

Ceramic antenna

2.4

Slot antenna

A slot antenna consists of a metal surface, usually a flat plane, with a hole or slot cut into it.

When the plate is driven as an antenna by a driving frequency, the slot radiates

electromagnetic waves in a similar way to a dipole antenna. The shape and size of the slot,

as well as the driving frequency, determine the radiation distribution pattern.

Slot antennas are typically used at UHF and microwave frequencies when greater control of

the radiation pattern is required. The slot antenna is popular because it can be cut out of

whatever surface it is to be mounted on, and have radiation patterns that are roughly

omnidirectional (similar to a linear wire antenna). The polarization of a slot antenna is linear.

The slot size, shape, and what is found inside the cavity of the cut-out antenna, offer design

variables that can be used to tune performance.

Slot antennas are widely used in radar antennas, for the sector antennas, for cell phone

base stations, and are often found in standard desktop microwave sources.

A slot antenna's main advantages are its size, design simplicity, robustness, and convenient

adaptation to mass production using PC board technology.

Two examples of slot antenna and relative 3D radiation pattern are shown in Figure 20.

Figure 20.

Slot antenna implementation and 3D radiation pattern

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