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Wireless & Mobility · Intermediate

Decibel Relative to Dipole (dBd)

Antenna gain in decibels compared with a half-wave dipole antenna.

Definition

dBd uses a half-wave dipole as the reference instead of an isotropic radiator. Because a dipole itself has 2.14 dBi of gain, dBi = dBd + 2.14. dBd is common in cellular and land-mobile radio specifications.

Example

A 3 dBd antenna has 5.14 dBi of gain.

Exam tip

If two antennas are compared, convert both to dBi first.

Related terms