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phased.Radiator System object

Package: phased

Narrowband signal radiator

Description

The phased.Radiator object implements a narrowband signal radiator. For any antenna element, microphone element, or array, the radiator creates the outgoing signal that is to be propagated to the far field using the phased.FreeSpace object. You can think of the output of phased.Radiator as the field at a reference distance from the element or center of the array. The signal can represent a polarized or nonpolarized field depending upon whether the element or array supports polarization and the value of the EnablePolarization property. For arrays, you can create a superposed field of all array elements signals or a separate field for each element depending upon the value of the CombineRadiatedSignals property.

To compute the radiated signal from the sensor(s):

  1. Define and set up your radiator. See Construction.

  2. Call step to compute the radiated signal according to the properties of phased.Radiator. The behavior of step is specific to each object in the toolbox.

Construction

H = phased.Radiator creates a narrowband signal radiator System object™, H. The object returns radiated narrowband signals for given directions using a sensor array or a single element.

H = phased.Radiator(Name,Value) creates a radiator object, H, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

Properties

Sensor

Sensor element or sensor array

Sensor element or sensor array specified as a System object in the Phased Array System Toolbox™. A sensor array can contain subarrays.

Default: phased.ULA with default property values

PropagationSpeed

Signal propagation speed

Specify the propagation speed of the signal, in meters per second, as a positive scalar.

Default: Speed of light

OperatingFrequency

System operating frequency

Specify the operating frequency of the system in hertz as a positive scalar. The default value corresponds to 300 MHz.

Default: 3e8

CombineRadiatedSignals

Combine radiated signals

Set this property to true to combine radiated signals from all radiating elements. Set this property to false to obtain the radiated signal for each radiating element. If the Sensor property is an array that contains subarrays, the CombineRadiatedSignals property must be true.

Default: true

EnablePolarization

Enable Polarization

Set this property to true to simulate the radiation of polarized waves. Set this property to false to ignore polarization. This property applies when the sensor specified in the Sensor property is capable of simulating polarization.

Default: false

WeightsInputPort

Enable weights input

To specify weights, set this property to true and then use the corresponding input argument when you invoke step. If you do not want to specify weights, set this property to false.

Default: false

Methods

cloneCreate radiator object with same property values
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs from step method
isLockedLocked status for input attributes and nontunable properties
releaseAllow property value and input characteristics changes
stepRadiate signals

Examples

Radiate the signal from a single isotropic antenna.

ha = phased.IsotropicAntennaElement;
hr = phased.Radiator('Sensor',ha,'OperatingFrequency',300e6);
x = [1;1];
radiatingAngle = [30 10]';
y = step(hr,x,radiatingAngle);
 

Radiate a far field signal with a 5-element array.

ha = phased.ULA('NumElements',5);
hr = phased.Radiator('Sensor',ha,'OperatingFrequency',300e6);
x = [1;1];
radiatingAngle = [30 10; 20 0]'; % two directions
y = step(hr,x,radiatingAngle);
 

Radiate signal with a 3-element antenna array. Each antenna radiates a separate signal to a separate direction.

ha = phased.ULA('NumElements',3);
hr = phased.Radiator('Sensor',ha,'OperatingFrequency',1e9,...
    'CombineRadiatedSignals',false);
x = [1 2 3;1 2 3];
radiatingAngle = [10 0; 20 5; 45 2]'; % One angle for one antenna
y = step(hr,x,radiatingAngle);

References

[1] Van Trees, H. Optimum Array Processing. New York: Wiley-Interscience, 2002.

See Also

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