Sensor array gain
ArrayGain object calculates the array gain
for a sensor array. The array
gain is defined as the signal to noise ratio (SNR) improvement
between the array output and the individual channel input, assuming
the noise is spatially white. It is related to the array response
but is not the same.
To compute the SNR gain of the antenna for specified directions:
Starting in R2016b, instead of using the
to perform the operation defined by the System object™, you can
call the object with arguments, as if it were a function. For example,
= step(obj,x) and
y = obj(x) perform
H = phased.ArrayGain creates an array gain System object,
This object calculates the array gain of a 2-element uniform linear
array for specified directions.
H = phased.ArrayGain( creates
and array-gain object,
H, with the specified
property Name set to the specified Value. You can specify additional
name-value pair arguments in any order as (
Sensor array specified as an array System object belonging
Signal propagation speed
Specify the propagation speed of the signal, in meters per second, as a positive scalar.
Default: Speed of light
Add input to specify weights
To specify weights, set this property to
|step||Calculate array gain of sensor array|
|Common to All System Objects|
Allow System object property value changes
Calculate the array gain for a 4-element uniform linear array (ULA) in the direction 30° azimuth and 20° elevation. The array operating frequency is 300 MHz.
fc = 300e6; array = phased.ULA(4); gain = phased.ArrayGain('SensorArray',array); g = gain(fc,[30;20])
g = -17.1783
The array gain is defined as the signal to noise ratio (SNR) improvement between the array output and the individual channel input, assuming the noise is spatially white. You can express the array gain as follows:
In this equation:
w is the vector of weights applied
on the sensor array. When you use
you can optionally specify weights by setting the
true and specifying the
step method syntax.
v is the steering vector representing
the array response toward a given direction. When you call the
ANG argument specifies the direction.
s is the input signal power.
N is the noise power.
H denotes the complex conjugate transpose.
For example, if a rectangular taper is used in the array, the array gain is the square of the array response normalized by the number of elements in the array.
 Guerci, J. R. Space-Time Adaptive Processing for Radar. Boston: Artech House, 2003.
 Van Trees, H. Optimum Array Processing. New York: Wiley-Interscience, 2002.
Usage notes and limitations:
Does not support arrays containing polarized antenna
elements, that is, the
See System Objects in MATLAB Code Generation (MATLAB Coder).