When trying to create a tilted antenna array, why do I get the error 'Tilt on elements with groundplane is not supported for arrays'?

I want to create an array of antennas and tilt the array. I can tilt an individual antenna by setting its 'Tilt' and 'TiltAxis' properties, but when I make an array of these antennas, I get an error. 

Answer 1

[MathWorks Support Team]

You can tilt the entire array as a whole by setting the 'Tilt' and 'TiltAxis' properties of the *antenna array* object, as opposed to setting those properties on the individual antenna object that you are using the construct the array.

If you want to construct an array of reflector-backed elements, where the antenna elements are all tilted by the same amount relative to the reflector, you can set the 'Tilt' and 'TiltAxix' properties of the reflector element's 'Exciter' property.

For example, instead of writing

clear;
c = physconst('LightSpeed');
frequency = 1e6;
lambda  = c / frequency;
length  = lambda / 2;
ground_plane_lw = lambda/2;
width   = lambda / 50;
num_elem = 8;

exciter = dipole(Length = length, ...
                 Width = width);
antenna_elem = dipoleCrossed(Element = exciter);
reflector_elem = reflector(GroundPlaneLength = ground_plane_lw, ...
                           GroundPlaneWidth = ground_plane_lw, ...
                           Spacing = lambda/4, ...
                           Exciter = antenna_elem, ...
                           Tilt = 90, ...
                           TiltAxis = [1 0 0]);
ca = circularArray(Element=reflector_elem, NumElements=num_elem);
layout(ca);

which will raise an error, write

clear;
c = physconst('LightSpeed');
frequency = 1e6;
lambda  = c / frequency;
length  = lambda / 2;
ground_plane_lw = lambda/2;
width   = lambda / 50;
num_elem = 8;

exciter = dipole(Length = length, ...
                 Width = width);
antenna_elem = dipoleCrossed(Element = exciter, ...
                             Tilt = 90, ... 
                             TiltAxis = [1 0 0]);
reflector_elem = reflector(GroundPlaneLength = ground_plane_lw, ...
                           GroundPlaneWidth = ground_plane_lw, ...
                           Spacing = lambda/4, ...
                           Exciter = antenna_elem);
ca = circularArray(Element=reflector_elem, NumElements=num_elem);
layout(ca);

which will work as intended.

See the following documentation page for more information and examples:

https://www.mathworks.com/help/antenna/ug/antenna-rotation.html