# A report onAntenna (radio) and Decibel

dBd: dB(dipole) – the gain of an antenna compared with the gain a half-wave dipole antenna. 0 dBd = 2.15 dBi

- Decibel

A circularly polarized antenna can be used to equally well match vertical or horizontal linear polarizations, suffering a 3 dB signal reduction.

## 4 related topics with Alpha

Theoretical point source of electromagnetic or sound waves which radiates the same intensity of radiation in all directions.

Theoretical point source of electromagnetic or sound waves which radiates the same intensity of radiation in all directions.

Isotropic radiators are used as reference radiators with which other sources are compared, for example in determining the gain of antennas.

It thus is said to have a directivity of 0 dBi (dB relative to isotropic) in all directions.

## Dipole antenna

In radio and telecommunications a dipole antenna or doublet is the simplest and most widely used class of antenna.

For a gain measured relative to a dipole, one says the antenna has a gain of "x dBd" (see decibel).

## Gain (electronics)

Measure of the ability of a two-port circuit to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal.

Measure of the ability of a two-port circuit to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal.

It is often expressed using the logarithmic decibel (dB) units ("dB gain").

The term gain has a different meaning in antenna design; antenna gain is the ratio of radiation intensity from a directional antenna to (red) of an ideal linear amplifier with a voltage gain of 3 with an arbitrary input signal.