What Is Antenna Efficiency?

Antenna efficiency refers to the ratio of the power radiated by the antenna (that is, the power that effectively converts the electromagnetic wave part) to the active power input to the antenna. It is a constant value less than 1.

Antenna efficiency refers to the ratio of the power radiated by the antenna (that is, the power that effectively converts the electromagnetic wave part) to the active power input to the antenna. It is a constant value less than 1.

Antenna efficiency is generally defined as the ratio of the radiated power of the antenna to the input power. Since antenna efficiency is the ratio of radiated power to input power, it naturally links the directivity coefficient and gain.

Antenna efficiency measurement method: measure the quality of the antenna and the return loss at the predetermined operating frequency, and obtain the specific heat capacity of the antenna according to the material of the antenna; divide the antenna into multiple equal parts according to the area; divide the frequency to the predetermined operating frequency, A signal with a power of a predetermined power is input to the antenna to make the antenna work; when the antenna reaches thermal equilibrium, measure the working temperature value of each aliquot and the ambient temperature around the antenna; according to the specific heat capacity value, mass, and working temperature of each aliquot And the ambient temperature value is calculated to obtain the heat dissipation of the antenna, and the input power of the antenna is calculated according to the predetermined power and return loss; the efficiency of the antenna is calculated according to the input power and heat dissipation.

Antenna efficiency is generally defined as the ratio of the radiated power of the antenna to the input power, that is:

The corresponding resistance relationship is expressed as:

Since the antenna efficiency is the ratio of the radiated power to the input power, it is natural to associate the directivity coefficient with the gain. The relationship is:

For high gain aperture antennas, the overall antenna efficiency

The relationship with antenna gain is:

Where antenna efficiency

Should be the product of multiple factors, namely:

Where

Is radiation efficiency,

Is the aperture efficiency,

Contains other factors that affect antenna gain, such as illumination loss, aperture occlusion, surface tolerance, depolarization loss, and more. ^[1]