Directivity quantifies the degree to which an antenna focuses its transmitted energy in a single direction compared to an isotropic radiator that broadcasts equally in all directions. It is expressed in decibels isotropic (dBi) and determines the maximum theoretical gain before accounting for electrical losses. High directivity is essential for point-to-point microwave links, while low directivity suits cellular base stations needing wide coverage.
The dish has a directivity of 30 dBi, so we need to align it perfectly with the remote site.
Related terms
Omnidirectional
An antenna or microphone pattern that radiates or receives equally in all directions horizontally.
Spot beam
A highly concentrated satellite signal directed at a specific, limited geographic area on the ground.
ERP
Effective radiated power is the total RF power emitted by an antenna in its main direction of focus.