Convert effective aperture to gain
Compute Antenna Gain
An antenna has an effective aperture of 3 square meters. Find the antenna gain when used to capture an electromagnetic wave with a wavelength of 10 cm.
g = aperture2gain(3,0.1)
g = 35.7633
A — Antenna effective aperture
positive scalar |
N-element vector of positive values
Antenna effective aperture, specified as a positive scalar or as an
N-element real-valued vector of positive values. If
A is a vector, each element of
A corresponds is the effective aperture of a
different antenna. See Gain and Effective Aperture for a discussion of aperture and
gain. Units are in square meters.
lambda — Wavelength of the incident electromagnetic wave
Wavelength of the incident electromagnetic wave, specified as a positive
scalar. The same wavelength applies to all antennas in
A. The wavelength of an electromagnetic wave is the
ratio of the wave propagation speed to the frequency. Units are in
GdB — Antenna gain
scalar | N-element real-valued vector
Antenna gain, returned as a scalar or as an N-element
real-valued vector. The elements of
GdB represent the
gain corresponding to the elements in
A. The size of
GdB equals the size of
Units are in dBi.
Gain and Effective Aperture
The effective aperture describes how much energy is captured by an antenna from an incident electromagnetic plane wave. The effective area of the antenna and is not the same as the actual physical area. The array gain of an antenna G is related to its effective aperture Ae by:
where λ is the wavelength of the incident electromagnetic wave. For a fixed wavelength, the antenna gain is proportional to the effective aperture. For a fixed effective aperture, the antenna gain is inversely proportional to the square of the wavelength.
The gain expressed in dBi (GdB) is
The effective antenna aperture can be derived from the gain in dB using
 Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill, 2001.
 Richards, M. Fundamentals of Radar Signal Processing, New York: McGraw-Hill, 2005.
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
Does not support variable-size inputs.
Introduced in R2011a