agi.foundation.communications.antennas

(agi.foundation.communications-2024r3.jar)

Class PhasedArrayGainPattern

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.communications.antennas.BaseGainPattern

agi.foundation.communications.antennas.RadioFrequencyGainPattern

agi.foundation.communications.antennas.PhasedArrayGainPattern

All Implemented Interfaces:

IAntennaGainService, ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider

public class PhasedArrayGainPattern
extends RadioFrequencyGainPattern

A RadioFrequencyGainPattern for modeling planar phased array antennas. The phased array model consists of many radiating elements. Each element is modeled as an isotropic pattern. By modifying the excitation (amplitude and phase) of each element differently, a phased array antenna can electronically steer its maximum gain toward a particular direction or main radiation axis. A phased array antenna not only can steer its maximum gain in a particular direction, but it can also steer nulls toward other directions in an effort to prevent radiation to and from other directions. The act of altering each element's excitation is effectively accomplished through the assignment of weights to each element. This set of weights for a particular direction is called a steering vector and each weight is a complex number.

Constructor Summary

Constructors

Modifier	Constructor and Description
	PhasedArrayGainPattern() Initializes a new instance.
	PhasedArrayGainPattern(double designFrequency, double backLobeSuppression, Iterable<? extends PhasedArrayElement> elementPattern, PhasedArrayBeamformer beamformer) Initializes a new instance.
	PhasedArrayGainPattern(double designFrequency, double backLobeSuppression, Iterable<? extends PhasedArrayElement> elementPattern, PhasedArrayBeamformer beamformer, PhasedArrayElementFactor elementFactor) Initializes a new instance.
protected	PhasedArrayGainPattern(PhasedArrayGainPattern existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(PhasedArrayGainPattern other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(RadioFrequencyGainPattern other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
Object	clone(CopyContext context) Clones this object using the specified context.
protected int	computeCurrentDefinitionHashCode() Computes a hash code based on the current properties of this object.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
protected void	freezeAggregatedObjects() Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object.
SignalEvaluator	getApplyAntennaGainEvaluator(EvaluatorGroup group, Vector linkDirection, Axes antennaAxes, ISignalSource inputSignal, SignalPropagationGraph graph) Get an evaluator which can modify a set of input signals based on link geometry and the gain pattern.
double	getBackLobeSuppression() Gets the phased array back lobe suppression value applied to the antenna gain for directions with a negative z component (back lobe).
PhasedArrayBeamformer	getBeamformer() Gets the phased array beam former.
double	getDesignFrequency() Gets the phased array design frequency.
PhasedArrayElementFactor	getElementFactor() Gets the element factor.
DefinitionalObjectCollection<PhasedArrayElement>	getElementPattern() Gets the list of PhasedArrayElement instances which form the phased arrays element pattern.
void	setBackLobeSuppression(double value) Sets the phased array back lobe suppression value applied to the antenna gain for directions with a negative z component (back lobe).
void	setBeamformer(PhasedArrayBeamformer value) Sets the phased array beam former.
void	setDesignFrequency(double value) Sets the phased array design frequency.
void	setElementFactor(PhasedArrayElementFactor value) Sets the element factor.

Methods inherited from class agi.foundation.communications.antennas.RadioFrequencyGainPattern

checkForSameDefinition

Methods inherited from class agi.foundation.communications.antennas.BaseGainPattern

checkForSameDefinition, getAntennaGainEvaluator, getAntennaGainEvaluator, getService

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, getCollectionHashCode, getCollectionHashCode, getCollectionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDictionaryHashCode, getIsFrozen, isSameDefinition, throwIfFrozen

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PhasedArrayGainPattern

public PhasedArrayGainPattern()

Initializes a new instance.

The DesignFrequency (get / set) defaults to 14.5e9 Hz and BackLobeSuppression (get / set) defaults to 100.0 units. ElementPattern (get) is initialized to an empty list and Beamformer (get / set) is initialized to a default instance of MinimumVarianceDistortionlessResponseBeamformer.

PhasedArrayGainPattern

public PhasedArrayGainPattern(double designFrequency,
                              double backLobeSuppression,
                              @Nonnull
                              Iterable<? extends PhasedArrayElement> elementPattern,
                              @Nonnull
                              PhasedArrayBeamformer beamformer)

Initializes a new instance.

Parameters:

designFrequency - The design frequency of the antenna. Determines the wavelength used to space the elements in the xy plane of the antenna.

backLobeSuppression - The back lobe suppression value applied to the antenna gain when the link direction has a negative z component (back lobe).

elementPattern - The list of PhasedArrayElement instances which comprise the element pattern.

beamformer - The phased array beam former used to steer the antenna beams.

PhasedArrayGainPattern

public PhasedArrayGainPattern(double designFrequency,
                              double backLobeSuppression,
                              @Nonnull
                              Iterable<? extends PhasedArrayElement> elementPattern,
                              @Nonnull
                              PhasedArrayBeamformer beamformer,
                              @Nullable
                              PhasedArrayElementFactor elementFactor)

Initializes a new instance.

Parameters:

designFrequency - The design frequency of the antenna. Determines the wavelength used to space the elements in the xy plane of the antenna.

backLobeSuppression - The back lobe suppression value applied to the antenna gain when the link direction has a negative z component (back lobe).

elementPattern - The list of PhasedArrayElement instances which comprise the element pattern.

beamformer - The phased array beam former used to steer the antenna beams.

elementFactor - The phased array element factor used to apply the individual element pattern. If the element factor is null, no element factor will be applied to the antenna gain.

PhasedArrayGainPattern

protected PhasedArrayGainPattern(@Nonnull
                                 PhasedArrayGainPattern existingInstance,
                                 @Nonnull
                                 CopyContext context)

Initializes a new instance as a copy of an existing instance.

See ICloneWithContext.clone(CopyContext) for more information about how to implement this constructor in a derived class.

Parameters:

existingInstance - The existing instance to copy.

context - A CopyContext that controls the depth of the copy.

Throws:

ArgumentNullException - Thrown when existingInstance or context is null.

Method Detail

clone

public Object clone(CopyContext context)

Clones this object using the specified context.

This method should be implemented to call a copy constructor on the class of the object being cloned. The copy constructor should take the CopyContext as a parameter in addition to the existing instance to copy. The copy constructor should first call CopyContext.addObjectMapping(T, T) to identify the newly constructed instance as a copy of the existing instance. It should then copy all fields, using CopyContext.updateReference(T) to copy any reference fields.

A typical implementation of ICloneWithContext:

public static class MyClass implements ICloneWithContext {
    public MyClass(MyClass existingInstance, CopyContext context) {
        context.addObjectMapping(existingInstance, this);
        someReference = context.updateReference(existingInstance.someReference);
    }

    @Override
    public final Object clone(CopyContext context) {
        return new MyClass(this, context);
    }

    private Object someReference;
}

In general, all fields that are reference types should be copied with a call to CopyContext.updateReference(T). There are a couple of exceptions:

1. Fields that are aggregate parts of the object should always be copied. A referenced object is an aggregate if properties or methods on the object being copied can modify the externally-visible value of the referenced object.
2. If the semantics of the referenced object require that it have a single parent, owner, context, etc., and the object being copied is that parent, owner, or context, then the referenced object should always be copied.

If one of these exceptions applies, the CopyContext should be given an opportunity to update the reference before the reference is copied explicitly. Use CopyContext.updateReference(T) to update the reference. If CopyContext.updateReference(T) returns the original object, indicating that the context does not have a replacement registered, then copy the object manually by invoking a Clone method, a copy constructor, or by manually constructing a new instance and copying the values.

alwaysCopy = context.updateReference(existingInstance.alwaysCopy);
if (existingInstance.alwaysCopy != null && alwaysCopy == existingInstance.alwaysCopy) {
    alwaysCopy = (AlwaysCopy) existingInstance.alwaysCopy.clone(context);
}

If you are implementing an evaluator (a class that implements IEvaluator), the IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) method shares some responsibilities with the copy context constructor. Code duplication can be avoided by doing the following:

1. For references to other evaluators ONLY, simply assign the reference in the constructor instead of calling CopyContext.updateReference(T). You should still call CopyContext.updateReference(T) on any references to non-evaluators.
2. Call IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as the last line in the constructor and pass it the same CopyContext passed to the constructor.
3. Implement IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as normal. See the reference documentation for IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) for more information on implementing that method.

public MyClass(MyClass existingInstance, CopyContext context) {
    super(existingInstance, context);
    someReference = context.updateReference(existingInstance.someReference);
    evaluatorReference = existingInstance.evaluatorReference;
    updateEvaluatorReferences(context);
}

@Override
public void updateEvaluatorReferences(CopyContext context) {
    evaluatorReference = context.updateReference(evaluatorReference);
}

@Override
public Object clone(CopyContext context) {
    return new MyClass(this, context);
}

private Object someReference;
private IEvaluator evaluatorReference;

Specified by:

clone in interface ICloneWithContext

Specified by:

clone in class DefinitionalObject

Parameters:

context - The context to use to perform the copy.

Returns:

A new instance which is a copy of this object.

checkForSameDefinition

protected final boolean checkForSameDefinition(RadioFrequencyGainPattern other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Specified by:

checkForSameDefinition in class RadioFrequencyGainPattern

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

checkForSameDefinition

protected boolean checkForSameDefinition(PhasedArrayGainPattern other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

computeCurrentDefinitionHashCode

protected int computeCurrentDefinitionHashCode()

Computes a hash code based on the current properties of this object. Derived classes MUST override this method and compute a hash code that combines: a unique hash code seed, the base implementation result, and the hash codes of all new fields introduced by the derived class which are used in the PhasedArrayGainPattern.checkForSameDefinition(agi.foundation.communications.antennas.RadioFrequencyGainPattern) method.

Overrides:

computeCurrentDefinitionHashCode in class RadioFrequencyGainPattern

Returns:

The computed hash code.

enumerateDependencies

public void enumerateDependencies(DependencyEnumerator enumerator)

Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon. Derived classes which contain additional dependencies MUST override this method, call the base implementation, and enumerate dependencies introduced by the derived class.

Specified by:

enumerateDependencies in interface IEnumerateDependencies

Overrides:

enumerateDependencies in class DefinitionalObject

Parameters:

enumerator - The enumerator that is informed of the dependencies of this object.

freezeAggregatedObjects

protected void freezeAggregatedObjects()

Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object. Derived classes which contain additional aggregated objects MUST override this method, call the base implementation, and freeze aggregated objects introduced by the derived class. The objects that need to be frozen in this method are frequently created in this object's constructor and are not settable via properties.

Overrides:

freezeAggregatedObjects in class DefinitionalObject

getApplyAntennaGainEvaluator

public SignalEvaluator getApplyAntennaGainEvaluator(EvaluatorGroup group,
                                                    Vector linkDirection,
                                                    Axes antennaAxes,
                                                    ISignalSource inputSignal,
                                                    SignalPropagationGraph graph)

Get an evaluator which can modify a set of input signals based on link geometry and the gain pattern.

Specified by:

getApplyAntennaGainEvaluator in interface IAntennaGainService

Specified by:

getApplyAntennaGainEvaluator in class BaseGainPattern

Parameters:

group - The evaluator group in which to create the evaluator.

linkDirection - The direction of the link relative to the antenna axes.

antennaAxes - The orientation of the antenna.

inputSignal - The source for the signals on which to apply the gain.

graph - The graph of communication links to use in the analysis.

Returns:

An evaluator which produces the modified set of signals with gains applied.

Throws:

ArgumentNullException - Thrown if any of the arguments are null.

PropertyInvalidException - Thrown if the Beamformer (get / set) property returns null.

PropertyInvalidException - Thrown if the DesignFrequency (get / set) property returns a value greater than CommunicationsConstants.MaximumRfFrequency or less than CommunicationsConstants.MinimumRfFrequency.

PropertyInvalidException - Thrown if the number of enabled elements in the ElementPattern (get) is less than 2.

ArgumentNullException - Thrown when group, linkDirection, antennaAxes, inputSignal, or graph is null.

getElementPattern

@Nonnull
public final DefinitionalObjectCollection<PhasedArrayElement> getElementPattern()

Gets the list of PhasedArrayElement instances which form the phased arrays element pattern.

getElementFactor

@Nullable
public final PhasedArrayElementFactor getElementFactor()

Gets the element factor. If set to null, the element factor will not be applied to the antenna gain pattern.

setElementFactor

public final void setElementFactor(@Nullable
                                   PhasedArrayElementFactor value)

Sets the element factor. If set to null, the element factor will not be applied to the antenna gain pattern.

getBeamformer

public final PhasedArrayBeamformer getBeamformer()

Gets the phased array beam former.

setBeamformer

public final void setBeamformer(PhasedArrayBeamformer value)

Sets the phased array beam former.

getDesignFrequency

public final double getDesignFrequency()

Gets the phased array design frequency. The design frequency determines the wavelength used to space the elements in the xy plane of the antenna.

setDesignFrequency

public final void setDesignFrequency(double value)

Sets the phased array design frequency. The design frequency determines the wavelength used to space the elements in the xy plane of the antenna.

getBackLobeSuppression

public final double getBackLobeSuppression()

Gets the phased array back lobe suppression value applied to the antenna gain for directions with a negative z component (back lobe).

setBackLobeSuppression

public final void setBackLobeSuppression(double value)

Sets the phased array back lobe suppression value applied to the antenna gain for directions with a negative z component (back lobe).