Using CustomAntennaElement as an exciter for the cassegrain object.

Greetings. According to the documentation phased.CustomAntennaElement can be used as an exciter for the cassegrain antenna object.

Here are the properties of my created CustomAntennaElement:

FrequencyVector: [6.8000e+09 6.9000e+09 7.0000e+09]
FrequencyResponse: [0 0 0]
PatternCoordinateSystem: 'phi-theta'
PhiAngles: [0 0.5000 1 1.5000 2 2.5000 3 3.5000 4 4.5000 5 5.5000 6 6.5000 7 7.5000 8 8.5000 9 9.5000 10 10.5000 11 11.5000 12 12.5000 13 13.5000 14 14.5000 15 15.5000 16 … ]
ThetaAngles: [0 0.5000 1 1.5000 2 2.5000 3 3.5000 4 4.5000 5 5.5000 6 6.5000 7 7.5000 8 8.5000 9 9.5000 10 10.5000 11 11.5000 12 12.5000 13 13.5000 14 14.5000 15 15.5000 16 … ]
SpecifyPolarizationPattern: false
MagnitudePattern: [361×720×18 double]
PhasePattern: [361×720×18 double]
MatchArrayNormal: true

I'm creating a new cassegrain object at line 18 using:

ant = cassegrain(Exciter=myCustomAntennaElement, Radius=[radius_primary radius_secondary],FocalLength=[primary_reflector_focal_length secondary_reflector_focal_length]);

And here are the errors I am receiving:

Error using phased.CustomAntennaElement/parenReference

Not enough input arguments. Expected 2 (in addition to System object), got 1.

Error in em.MeshGeometry/checkObjectClass

Error in em.ParabolicAntenna/set.Exciter (line 44)

checkObjectClass(obj,propVal)

Error in em.ParabolicAntenna (line 34)

obj.Exciter = aExciter;

Error in cassegrain (line 101)

obj = [e-mail](parserObj.Results.Exciter,...

Error in CassegrainAntenna (line 18)

It breaks inside ParabolicAntenna.set.Exciter function (I will provide only the part of it) at the checkObjectClass method:

function set.Exciter(obj,propVal)
checkObjectClass(obj,propVal)
objClass = class(propVal);
excludelist = {'cavity'...

Here propVal equals the CustomAntennaElement provided earlier, and obj equals the cassegrain object:

obj = 

cassegrain with properties:

Exciter: []
Radius: []
FocalLength: []
Tilt: []
TiltAxis: []
Load: []
SolverType: 'MoM'

Will gladly appreciate any helpful suggestions.

Answer 1

[Govind KM]

Hi @Tood,

From what I understand, you are facing the mentioned error when trying to set a phased.customAntennaElement as exciter for a cassegrain antenna object. This is because the cassegrain object supports setting antenna and array objects as an exciter, not individual antenna elements. In case of custom antennas, customAntennaGeometry, customAntennaMesh and customAntenna objects can be set as Exciters:

https://www.mathworks.com/help/antenna/ref/cassegrain.html#mw_11b30d17-b173-4fc3-9ebd-23dd8d684611:~:text=Custom%20antennas%3A%20customAntennaGeometry%2C%20customAntennaMesh%2C%20customAntenna

A potential workaround could be to use the custom antenna objects mentioned above instead of a custom antenna element.

Hope this is helpful!