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Directivity of Antenna Formula:
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Directivity of antenna measures the degree to which the radiation emitted is concentrated in a single direction. It is a fundamental parameter in antenna theory that quantifies how directional an antenna's radiation pattern is.
The calculator uses the Directivity formula:
Where:
Explanation: The directivity is calculated as the ratio of the radiation intensity in a given direction to the average radiation intensity over all directions.
Details: Directivity is crucial in antenna design as it determines how well an antenna focuses energy in specific directions. Higher directivity indicates a more focused beam, which is essential for long-distance communication and reducing interference.
Tips: Enter Radiation Intensity and Average Radiation Intensity values in Watt per Steradian. Both values must be positive numbers greater than zero.
Q1: What is the difference between directivity and gain?
A: Directivity measures the concentration of radiation in a particular direction, while gain accounts for both the directivity and the efficiency of the antenna.
Q2: What are typical directivity values for common antennas?
A: Isotropic antennas have a directivity of 1 (0 dBi), dipole antennas have about 1.64 (2.15 dBi), while high-gain parabolic dishes can have directivities of 30 dBi or more.
Q3: How is directivity related to beamwidth?
A: Generally, higher directivity corresponds to narrower beamwidth. As an antenna focuses energy into a tighter beam, its directivity increases.
Q4: Can directivity be less than 1?
A: No, directivity cannot be less than 1. The minimum directivity of 1 represents an isotropic radiator that radiates equally in all directions.
Q5: How is directivity measured in practice?
A: Directivity is typically calculated from measured radiation patterns by integrating the power over all directions to find the average radiation intensity.