Radar Antenna Gain Formula

(Revised June 2024)

Computing Antenna Gain

Where:

G: Antenna Gain (center of mainlobe)
AArea: Antenna Area
AEff: Antenna Efficiency (see table below)
λ: Wavelength

NOTE: Both the Antenna Area and Wavelength must be in the same measurement units; e.g. if the antenna area is in square meters, the wavelength must be in meters as well.

Typical Antenna Efficiency Factors

1

Uniformly illuminated aperture (Practical impossibility)

0.6 to 0.8

Planar Arrays

As low as 0.45

Parabolic Reflectors

Fully Explained Example

EXAMPLE: What is the gain of a 60 cm diameter circular antenna operating in the 3-cm wavelength with an average efficiency factor of 70%?

Basic math gives us a surface area of 2,827.43 square cm for the antenna.

4π ((2.827.43 cm2 * 0.7) / 32) = 2,763.49

Converting the answer to dB gives us:

10 * log10(2,763.49) = 34.41 dB

An antenna gain of 34.41 dB.

Basic Antenna Gain Calculator

This calculator incorporates the basic gain formula as on this page.

Wavelength
Antenna Area
Antenna Efficiency

Antenna Gain
Antenna Gain (dB)

Complex Antenna Gain Calculator

This calculator incorporates the Radar Wavelength Formula found HERE.

Frequency (MHz)
Antenna Diameter in Antenna Efficiency

Typical Antenna Efficiency Factors

1

Uniformly illuminated aperture (Practical impossibility)

0.6 to 0.8

Planar Arrays

As low as 0.45

Parabolic Reflectors

Antenna Area of   
Antenna Gain
Antenna Gain (dB)