patternAzimuth

System object: phased.ConformalArray
Package: phased

Plot conformal array directivity or pattern versus azimuth

Syntax

```patternAzimuth(sArray,FREQ) patternAzimuth(sArray,FREQ,EL) patternAzimuth(sArray,FREQ,EL,Name,Value) PAT = patternAzimuth(___) ```

Description

`patternAzimuth(sArray,FREQ)` plots the 2-D array directivity pattern versus azimuth (in dBi) for the array `sArray` at zero degrees elevation angle. 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.

`patternAzimuth(sArray,FREQ,EL)`, in addition, plots the 2-D array directivity pattern versus azimuth (in dBi) for the array `sArray` at the elevation angle specified by `EL`. When `EL` is a vector, multiple overlaid plots are created.

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

`PAT = patternAzimuth(___)` returns the array pattern. `PAT` is a matrix whose entries represent the pattern at corresponding sampling points specified by the `'Azimuth'` parameter and the `EL` input argument.

Input Arguments

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Conformal array, specified as a `phased.ConformalArray` System object.

Example: `sArray= phased.ConformalArray;`

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`

Elevation angles for computing sensor or array directivities and patterns, specified as a 1-by-N real-valued row vector. The quantity N is the number of requested elevation directions. Angle units are in degrees. The elevation angle must lie between –90° and 90°.

The elevation angle is the angle between the direction vector and the xy plane. When measured toward the z-axis, this angle is positive.

Example: `[0,10,20]`

Data Types: `double`

Name-Value Pair Arguments

Specify optional comma-separated pairs of `Name,Value` arguments. `Name` is the argument name and `Value` is the corresponding value. `Name` must appear inside quotes. You can specify several name and value pair arguments in any order as `Name1,Value1,...,NameN,ValueN`.

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`

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`

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

Note

Use complex weights to steer the array response toward different directions. You can create weights using the `phased.SteeringVector` System object or you can compute your own weights. In general, you apply Hermitian conjugation before using weights in any Phased Array System Toolbox™ function or System object such as `phased.Radiator` or `phased.Collector`. However, for the `directivity`, `pattern`, `patternAzimuth`, and `patternElevation` methods of any array System object use the steering vector without conjugation.

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

Data Types: `double`
Complex Number Support: Yes

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

Example: `'Azimuth',[-90:2:90]`

Data Types: `double`

Output Arguments

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

Examples

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Construct a 5-element acoustic cross array (UCA) using the ConformalArray System object. Assume the operating frequency is 4 kHz. A typical value for the speed of sound in seawater is 1500.0 m/s. Plot the array patterns at two different elevation angles.

Construct and view array

```N = 5; fc = 4000; c = 1500.0; lam = c/fc; x = zeros(1,N); y = [-1,0,1,0,0]*lam/2; z = [0,0,0,-1,1]*lam/2; sMic = phased.OmnidirectionalMicrophoneElement(... 'FrequencyRange',[0,10000],'BackBaffled',true); sArray = phased.ConformalArray('Element',sMic,... 'ElementPosition',[x;y;z],... 'ElementNormal',[zeros(1,N);zeros(1,N)]); viewArray(sArray)```

Plot azimuth pattern for magnitude

```fc = 4000; c = 1500.0; patternAzimuth(sArray,fc,[0,20],... 'PropagationSpeed',c,... 'Type','efield')```

Plot azimuth pattern for directivity

```patternAzimuth(sArray,fc,[0,20],... 'PropagationSpeed',c,... 'Type','directivity')```