Directivity of antenna

1. What is meant by directivity of antenna?
2. What is the formula of directivity?
3. What is gain and directivity?
4. Why is directivity important in antenna?

What is meant by directivity of antenna?

9.3 Directivity. Directivity of an antenna is defined as the ratio of the radiation intensity in a given direction from the antenna to the radiation intensity averaged over all directions. The average radiation intensity is equal to the total power radiated by the antenna divided by 4π.

What is the formula of directivity?

Antenna Directivity D = maximum radiation intensity of a test antenna / average radiation intensity of test antenna. Therefore D= 4 π(maximum radiation intensity)/total radiation power.

What is gain and directivity?

Directivity defines the concentration of radiated power in a particular direction, whereas Gain specifies the concentration of input power in a particular direction. Gain is the combination of directivity and electrical efficiency.

Why is directivity important in antenna?

An antenna's directivity is greater than its gain by an efficiency factor, radiation efficiency. Directivity is an important measure because many antennas and optical systems are designed to radiate electromagnetic waves in a single direction or over a narrow-angle.