plotResponse

System object: phased.PartitionedArray
Package: phased

Plot response pattern of array

Syntax

plotResponse(H,FREQ,V)
plotResponse(H,FREQ,V,Name,Value)
hPlot = plotResponse(___)


Description

plotResponse(H,FREQ,V) plots the array response pattern along the azimuth cut, where the elevation angle is 0. The operating frequency is specified in FREQ. The propagation speed is specified in V.

plotResponse(H,FREQ,V,Name,Value) plots the array response with additional options specified by one or more Name,Value pair arguments.

hPlot = plotResponse(___) returns handles of the lines or surface in the figure window, using any of the input arguments in the previous syntaxes.

Input Arguments

H	Array object.
FREQ	Operating frequency in hertz. Typical values are within the range specified by a property of H.Array.Element. That property is named FrequencyRange or FrequencyVector, depending on the type of element in the array. The element has zero response at frequencies outside that range. If FREQ is a nonscalar row vector, the plot shows multiple frequency responses on the same axes.
V	Propagation speed in meters per second.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

CutAngle	Cut angle specified as a scalar. This argument is applicable only when RespCut is 'Az' or 'El'. If RespCut is 'Az', CutAngle must be between –90 and 90. If RespCut is 'El', CutAngle must be between –180 and 180. Default: 0
Format	Format of the plot, using one of 'Line', 'Polar', or 'UV'. If you set Format to 'UV', FREQ must be a scalar. Default: 'Line'
NormalizeResponse	Set this value to true to normalize the response pattern. Set this value to false to plot the response pattern without normalizing it. This parameter is not applicable when you set the Unit parameter value to 'dbi'. Default: true
OverlayFreq	Set this value to true to overlay pattern cuts in a 2-D line plot. Set this value to false to plot pattern cuts against frequency in a 3-D waterfall plot. If this value is false, then FREQ must be a vector with at least two entries. This parameter applies only when Format is not 'Polar' and RespCut is not '3D'. Default: true
Polarization	Specify the polarization options for plotting the array response pattern. The allowable values are |'None' | 'Combined' | 'H' | 'V' | where: 'None' specifies plotting a nonpolarized response pattern 'Combined' specifies plotting a combined polarization response pattern 'H' specifies plotting the horizontal polarization response pattern 'V' specifies plotting the vertical polarization response pattern For arrays that do not support polarization, the only allowed value is 'None'. This parameter is not applicable when you set the Unit parameter value to 'dbi'. Default: 'None'
RespCut	Cut of the response. Valid values depend on Format, as follows: If Format is 'Line' or 'Polar', the valid values of RespCut are 'Az', 'El', and '3D'. The default is 'Az'. If Format is 'UV', the valid values of RespCut are 'U' and '3D'. The default is 'U'. If you set RespCut to '3D', FREQ must be a scalar.
SteerAng	Subarray steering angle. SteerAng can be either a 2-element column vector or a scalar. If SteerAng is a 2-element column vector, it has the form [azimuth; elevation]. The azimuth angle must be between –180 and 180 degrees, inclusive. The elevation angle must be between –90 and 90 degrees, inclusive. If SteerAng is a scalar, it specifies the azimuth angle. In this case, the elevation angle is assumed to be 0. This option is applicable only if the SubarraySteering property of H is 'Phase' or 'Time'. Default: [0;0]
Unit	The unit of the plot. Valid values are 'db', 'mag', 'pow', or 'dbi'. This parameter determines the type of plot that is produced. Unit value Plot type db power pattern in dB scale mag field pattern pow power pattern dbi directivity Default: 'db'
Weights	Weight values applied to the array, specified as a length-N column vector or N-by-M matrix. The dimension N is the number of subarrays in the array. The interpretation of M depends upon whether the input argument FREQ is a scalar or row vector. Weights Dimension FREQ Dimension Purpose N-by-1 column vector Scalar or 1-by-M row vector Apply one set of weights for the same single frequency or all M frequencies. N-by-M matrix Scalar Apply all of the M different columns in Weights for the same single frequency. 1-by-M row vector Apply each of the M different columns in Weights for the corresponding frequency in FREQ.
AzimuthAngles	Azimuth angles for plotting subarray response, specified as a row vector. The AzimuthAngles parameter sets the display range and resolution of azimuth angles for visualizing the radiation pattern. This parameter is allowed only when the RespCut parameter is set to 'Az' or '3D' and the Format parameter is set to 'Line' or 'Polar'. The values of azimuth angles should lie between –180° and 180° and must be in nondecreasing order. When you set the RespCut parameter to '3D', you can set the AzimuthAngles and ElevationAngles parameters simultaneously. Default: [-180:180]
ElevationAngles	Elevation angles for plotting subarray response, specified as a row vector. The ElevationAngles parameter sets the display range and resolution of elevation angles for visualizing the radiation pattern. This parameter is allowed only when the RespCut parameter is set to 'El' or '3D' and the Format parameter is set to 'Line' or 'Polar'. The values of elevation angles should lie between –90° and 90° and must be in nondecreasing order. When you set the RespCut parameter to '3D', you can set the ElevationAngles and AzimuthAngles parameters simultaneously. Default: [-90:90]
UGrid	U coordinate values for plotting subarray response, specified as a row vector. The UGrid parameter sets the display range and resolution of the U coordinates for visualizing the radiation pattern in U/V space. This parameter is allowed only when the Format parameter is set to 'UV' and the RespCut parameter is set to 'U' or '3D'. The values of UGrid should be between –1 and 1 and should be specified in nondecreasing order. You can set the UGrid and VGrid parameters simultaneously. Default: [-1:0.01:1]
VGrid	V coordinate values for plotting subarray response, specified as a row vector. The VGrid parameter sets the display range and resolution of the V coordinates for visualizing the radiation pattern in U/V space. This parameter is allowed only when the Format parameter is set to 'UV' and the RespCut parameter is set to '3D'. The values of VGrid should be between –1 and 1 and should be specified in nondecreasing order. You can set the VGrid and UGrid parameters simultaneously. Default: [-1:0.01:1]

Examples

Azimuth Response of Partitioned ULA

Plot the azimuth response of a 4-element ULA partitioned into two 2-element ULA's. The element spacing is one-half wavelength.

Create the ULA, and partition it into two 2-element ULA's.

sULA = phased.ULA('NumElements',4,'ElementSpacing',0.5);
sPA = phased.PartitionedArray('Array',sULA,...
    'SubarraySelection',[1 1 0 0;0 0 1 1]);

Plot the azimuth response of the array. Assume the operating frequency is 1 GHz and the propagation speed is the speed of light.

fc = 1e9;
pattern(sPA,fc,[-180:180],0,'Type','powerdb',...
    'CoordinateSystem','polar',...
    'Normalize',true)

Plot Response and Directivity of Partitioned URA over Restricted Range of Angles

Convert a 2-by-6 URA of isotropic antenna elements into a 1-by-3 partitioned array so that each subarray of the partitioned array is a 2-by-2 URA. Assume that the frequency response of the elements lies between 1 and 6 GHz. The elements are spaced one-half wavelength apart corresponding to the highest frequency of the element response. Plot an azimuth cut from -50 to 50 degrees for two different sets of weights. For partitioned arrays, weights are applied to the subarrays instead of the elements.

Set up the partitioned array.

fmin = 1e9;
fmax = 6e9;
c = physconst('LightSpeed');
lam = c/fmax;
s_iso = phased.IsotropicAntennaElement(...
    'FrequencyRange',[fmin,fmax],...
    'BackBaffled',false);
s_ura = phased.URA('Element',s_iso,'Size',[2,6],...
    'ElementSpacing',[lam/2,lam/2]);
subarraymap = [[1,1,1,1,0,0,0,0,0,0,0,0];...
    [0,0,0,0,1,1,1,1,0,0,0,0];...
    [0,0,0,0,0,0,0,0,1,1,1,1]];
s_pa = phased.PartitionedArray('Array',s_ura,...
    'SubarraySelection',subarraymap);

Plot the response of the array at 5 GHz over the restricted range of azimuth angles.

fc = 5e9;
wts = [[1,1,1]',[.862,1.23,.862]'];
plotResponse(s_pa,fc,c,'RespCut','Az',...
    'AzimuthAngles',[-50:0.1:50],...
    'Unit','db','Format','Polar',...
    'Weights',wts);

The plot of the response shows the broadening of the main lobe and the reduction of the strength of the sidelobes caused by the weight tapering.

Next, plot an azimuth cut of the directivity of the array at 5 GHz over the restricted range of azimuth angles for the two different sets of weights.

fc = 5e9;
wts = [[1,1,1]',[.862,1.23,.862]'];
plotResponse(s_pa,fc,c,'RespCut','Az',...
    'AzimuthAngles',[-50:0.1:50],...
    'Unit','dbi',...
    'Weights',wts);