The Basics Of Antenna Arrays

In some instances, single-element antennas are unable to meet the gain or radiation pattern requirements of a particular application, such as satellite communications or point-to-point telecommunications. One possible solution to this problem is to combine several single antenna elements into an antenna array. This article will introduce the basic concepts of antenna array theory, without delving into the mathematics behind it.

Antenna Array Types And Radiation Patterns

Antenna elements can be arranged to form either a one- or two-dimensional antenna array. In outlining the different aspects of antenna arrays, we will use one-dimensional array examples for simplicity reasons. Each antenna exhibits a specific radiation pattern. When combined with several other antenna elements in an array, however, the overall radiation pattern of an antenna changes. This is due to the so-called "array factor," which quantifies the effect of combining radiating elements in an array without taking the element-specific radiation pattern into account.

The overall radiation pattern of an array is determined by combining the array factor with the radiation pattern of the antenna element. The overall radiation pattern results in a certain directivity and, through efficiency, in a certain gain. Directivity and gain are equal if the efficiency is 100%.