Polar Diagram

Polar Diagram of a wave is formed by drawing lines joining points of equal power or intensity of transmitted wave. In our earlier lesson, we had learnt about the power of radio wave based on the Inverse Squared Law of Electro Magnetic Radiation.


Generally, a polar diagram is drawn by connecting points where the power reduces to half of its transmitted power. Polar diagram of transmitter connects points of half the power transmitted and that of a receiver connects points of half the power received.

Shape of ariel determines the shape of polar diagram. For example, if we want all the power of to be directed in a particular direction, the ariel should be made accordingly. That’s the reason for differing size and shapes of various radar antenna. Polar diagram represents the relative values of strength of an electro magnetic wave in a certain direction from the ariel.

Polar diagram is drawn in three dimensional form and hence provides a representation of power radiated at various points in both the horizontal as well as the vertical plane.

In this lesson, we have learnt about the Polar Diagram of a transmitted radio wave. Having understood about the Polar Diagram, we shall learn about Surface Attenuation in our next lesson.