patternElevation

System object: phased.PartitionedArray
Namespace: phased

Plot partitioned array directivity or pattern versus elevation

Syntax

patternElevation(sArray,FREQ) patternElevation(sArray,FREQ,AZ) patternElevation(sArray,FREQ,AZ,Name,Value) PAT = patternElevation(___)

Description

patternElevation(sArray,FREQ) plots the 2-D array directivity pattern versus elevation (in dBi) for the array sArray at zero degrees azimuth angle. When AZ is a vector, multiple overlaid plots are created. The argument FREQ specifies the operating frequency.

The integration used when computing array directivity has a minimum sampling grid of 0.1 degrees. If an array pattern has a beamwidth smaller than this, the directivity value will be inaccurate.

patternElevation(sArray,FREQ,AZ), in addition, plots the 2-D element directivity pattern versus elevation (in dBi) at the azimuth angle specified by AZ. When AZ is a vector, multiple overlaid plots are created.

patternElevation(sArray,FREQ,AZ,Name,Value) plots the array pattern with additional options specified by one or more Name,Value pair arguments.

PAT = patternElevation(___) returns the array pattern. PAT is a matrix whose entries represent the pattern at corresponding sampling points specified by the 'Elevation' parameter and the AZ input argument.

Input Arguments

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`sArray` — Partitioned array
System object™

Partitioned array, specified as a phased.PartitionedArray System object.

Example: sArray= phased.PartitionedArray;

`FREQ` — Frequency for computing directivity and pattern
positive scalar

Frequency for computing directivity and pattern, specified as a positive scalar. Frequency units are in hertz.

For an antenna or microphone element, FREQ must lie within the range of values specified by the FrequencyRange or the FrequencyVector property of the element. Otherwise, the element produces no response and the directivity is returned as –Inf. Most elements use the FrequencyRange property except for phased.CustomAntennaElement and phased.CustomMicrophoneElement, which use the FrequencyVector property.
For an array of elements, FREQ must lie within the frequency range of the elements that make up the array. Otherwise, the array produces no response and the directivity is returned as –Inf.

Example: 1e8

Data Types: double

`AZ` — Azimuth angles for computing directivity and pattern
1-by-N real-valued row vector

Azimuth angles for computing sensor or array directivities and patterns, specified as a 1-by-N real-valued row vector where N is the number of desired azimuth directions. Angle units are in degrees. The azimuth angle must lie between –180° and 180°.

The azimuth angle is the angle between the x-axis and the projection of the direction vector onto the xy plane. This angle is positive when measured from the x-axis toward the y-axis.

Example: [0,10,20]

Data Types: double

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.

`Type` — Displayed pattern type
`'directivity'` (default) | `'efield'` | `'power'` | `'powerdb'`

Displayed pattern type, specified as the comma-separated pair consisting of 'Type' and one of

'directivity' — directivity pattern measured in dBi.
'efield' — field pattern of the sensor or array. For acoustic sensors, the displayed pattern is for the scalar sound field.
'power' — power pattern of the sensor or array defined as the square of the field pattern.
'powerdb' — power pattern converted to dB.

Example: 'powerdb'

Data Types: char

`PropagationSpeed` — Signal propagation speed
speed of light (default) | positive scalar

Signal propagation speed, specified as the comma-separated pair consisting of 'PropagationSpeed' and a positive scalar in meters per second.

Example: 'PropagationSpeed',physconst('LightSpeed')

Data Types: double

`Weights` — Subarray weights
M-by-1 complex-valued column vector

Subarray weights, specified as the comma-separated pair consisting of 'Weights' and an M-by-1 complex-valued column vector. Subarray weights are applied to the subarrays of the array to produce array steering, tapering, or both. The dimension M is the number of subarrays in the array.

Example: 'Weights',ones(10,1)

Data Types: double
Complex Number Support: Yes

`SteerAngle` — Subarray steering angle
`[0;0]` (default) | scalar | 2-element column vector

Subarray steering angle, specified as the comma-separated pair consisting of 'SteerAngle' and a scalar or a 2-by-1 column vector.

If 'SteerAngle' is a 2-by-1 column vector, it has the form [azimuth; elevation]. The azimuth angle must be between –180° and 180°, inclusive. The elevation angle must be between –90° and 90°, inclusive.

If 'SteerAngle' is a scalar, it specifies the azimuth angle only. In this case, the elevation angle is assumed to be 0.

This option applies only when the 'SubarraySteering' property of the System object is set to 'Phase' or 'Time'.

Example: 'SteerAngle',[20;30]

Data Types: double

`ElementWeights` — Weights applied to elements within subarray
`1` (default) | complex-valued N_SE-by-N matrix | 1-by-N cell array

Subarray element weights, specified as complex-valued N_SE-by-N matrix or 1-by-N cell array. Weights are applied to the individual elements within a subarray. Subarrays can have different dimensions and sizes.

If ElementWeights is a complex-valued N_SE-by-N matrix, N_SE is the number of elements in the largest subarray and N is the number of subarrays. Each column of the matrix specifies the weights for the corresponding subarray. Only the first K entries in each column are applied as weights where K is the number of elements in the corresponding subarray.

If ElementWeights is a 1-by-N cell array. Each cell contains a complex-valued column vector of weights for the corresponding subarray. The column vectors have lengths equal to the number of elements in the corresponding subarray.

Dependencies

To enable this name-value pair, set the SubarraySteering property of the array to 'Custom'.

Data Types: double
Complex Number Support: Yes

`Elevation` — Elevation angles
`[-180:180]` (default) | 1-by-P real-valued row vector

Elevation angles, specified as the comma-separated pair consisting of 'Elevation' and a 1-by-P real-valued row vector. Elevation angles define where the array pattern is calculated.

Example: 'Elevation',[-180:2:180]

Data Types: double

`Parent` — Handle to axis
scalar

Handle to the axes along which the array geometry is displayed specified as a scalar.

Output Arguments

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`PAT` — Array directivity or pattern
L-by-N real-valued matrix

Array directivity or pattern, returned as an L-by-N real-valued matrix. The dimension L is the number of elevation angles determined by the 'Elevation' name-value pair argument. The dimension N is the number of azimuth angles determined by the AZ argument.

Examples

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Plot Elevation Directivity of Partitioned URA

Open Live Script

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 the directivity for elevation angles from -45 to 45 degrees. For partitioned arrays, weights are applied to the subarrays instead of the elements.

Create partitioned array

fmin = 1e9;
fmax = 6e9;
c = physconst('LightSpeed');
lam = c/fmax;
sIso = phased.IsotropicAntennaElement(...
    'FrequencyRange',[fmin,fmax],...
    'BackBaffled',false);
sURA = phased.URA('Element',sIso,'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]];
sPA = phased.PartitionedArray('Array',sURA,...
    'SubarraySelection',subarraymap);

Plot elevation directivity pattern

Plot the response of the array at 5 GHz

fc = 5e9;
wts = [0.862,1.23,0.862]';
azimangle = 0;
patternElevation(sPA,fc,azimangle,...
    'Type','directivity',...
    'PropagationSpeed',physconst('LightSpeed'),...
    'Elevation',[-45:45],...
    'Weights',wts)

Figure contains an axes object. The hidden axes object contains 3 objects of type line, text. This object represents 5 GHz .

More About

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Directivity

Directivity describes the directionality of the radiation pattern of a sensor element or array of sensor elements.

Higher directivity is desired when you want to transmit more radiation in a specific direction. Directivity is the ratio of the transmitted radiant intensity in a specified direction to the radiant intensity transmitted by an isotropic radiator with the same total transmitted power

$D = 4 π \frac{U_{rad} (θ, φ)}{P_{total}}$

where U_rad(θ,φ) is the radiant intensity of a transmitter in the direction (θ,φ) and P_total is the total power transmitted by an isotropic radiator. For a receiving element or array, directivity measures the sensitivity toward radiation arriving from a specific direction. The principle of reciprocity shows that the directivity of an element or array used for reception equals the directivity of the same element or array used for transmission. When converted to decibels, the directivity is denoted as dBi. For information on directivity, read the notes on Element Directivity and Array Directivity.

Version History

Introduced in R2015a

patternElevation

Syntax

Description

Input Arguments

sArray — Partitioned array System object™

FREQ — Frequency for computing directivity and pattern positive scalar

AZ — Azimuth angles for computing directivity and pattern 1-by-N real-valued row vector

Name-Value Arguments

Type — Displayed pattern type 'directivity' (default) | 'efield' | 'power' | 'powerdb'

PropagationSpeed — Signal propagation speed speed of light (default) | positive scalar

Weights — Subarray weights M-by-1 complex-valued column vector

SteerAngle — Subarray steering angle [0;0] (default) | scalar | 2-element column vector

ElementWeights — Weights applied to elements within subarray 1 (default) | complex-valued NSE-by-N matrix | 1-by-N cell array

Dependencies

Elevation — Elevation angles [-180:180] (default) | 1-by-P real-valued row vector

Parent — Handle to axis scalar

Output Arguments

PAT — Array directivity or pattern L-by-N real-valued matrix

Examples

Plot Elevation Directivity of Partitioned URA

More About

Directivity

Version History

See Also

`sArray` — Partitioned array
System object™

`FREQ` — Frequency for computing directivity and pattern
positive scalar

`AZ` — Azimuth angles for computing directivity and pattern
1-by-N real-valued row vector

`Type` — Displayed pattern type
`'directivity'` (default) | `'efield'` | `'power'` | `'powerdb'`

`PropagationSpeed` — Signal propagation speed
speed of light (default) | positive scalar

`Weights` — Subarray weights
M-by-1 complex-valued column vector

`SteerAngle` — Subarray steering angle
`[0;0]` (default) | scalar | 2-element column vector

`ElementWeights` — Weights applied to elements within subarray
`1` (default) | complex-valued N_SE-by-N matrix | 1-by-N cell array

`Elevation` — Elevation angles
`[-180:180]` (default) | 1-by-P real-valued row vector

`Parent` — Handle to axis
scalar

`PAT` — Array directivity or pattern
L-by-N real-valued matrix