Figure 7.3 illustrates the power pattern in the principle planes of an array of five driven elements of the kind considered above.
Most dipole arrays use just one driven element and all the others are passive or parasitic elements.
The passive elements are dipoles which are simple strips of metal with no central break. In effect, they are linked together by the fields radiated backwards and forwards between elements. 7.4 shows two examples from the wide range of possible designs. It consists of one driven element plus one or more Directors on one side and a Reflector on the other. An incoming field sets up resonant currents on all the dipole elements.