# current

Current distribution on antenna or array surface

## Syntax

``current(object,frequency)``
``i = current(object,frequency)``
``[i,p] = current(object,frequency)``
``current(object,frequency,'dielectric')``
``[___] = current(object,frequency,'dielectric')``
``[___] = current(___,Name=Value)``

## Description

example

````current(object,frequency)` calculates and plots the absolute value of the current on the surface of the specified antenna or array `object` at the specified frequency.```

example

````i = current(object,frequency)` returns the components of the antenna or array surface current at the specified frequency in a Cartesian coordinate system.```
````[i,p] = current(object,frequency)` also returns the point at which the function performs the current calculation.```

example

````current(object,frequency,'dielectric')` calculates and plots the absolute value of the current at the specified frequency on the dielectric face of the antenna or array.```
````[___] = current(object,frequency,'dielectric')` returns the components of the current on the dielectric surface of the antenna or array at the specified frequency in a Cartesian coordinate system.```
````[___] = current(___,Name=Value)` specifies additional options using one or more name-value arguments.```

## Examples

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Calculate and plot the current distribution for a circular loop antenna at 70MHz frequency.

``` h = loopCircular; current(h,70e6);```

Calculate the current distribution of a default rectangular array at 70MHz frequency.

```h = rectangularArray; i = current(h,70e6)```
```i = 3×160 complex 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0012 + 0.0024i -0.0012 - 0.0023i 0.0031 + 0.0053i -0.0021 - 0.0035i 0.0017 + 0.0030i -0.0014 - 0.0026i -0.0004 - 0.0014i 0.0003 + 0.0013i 0.0010 + 0.0021i -0.0010 - 0.0021i 0.0014 + 0.0026i -0.0017 - 0.0029i -0.0008 - 0.0018i 0.0008 + 0.0018i 0.0001 + 0.0028i -0.0001 - 0.0013i 0.0005 + 0.0016i -0.0006 - 0.0016i -0.0016 - 0.0029i 0.0015 + 0.0028i -0.0010 - 0.0021i 0.0010 + 0.0021i -0.0001 - 0.0028i 0.0001 + 0.0013i -0.0003 - 0.0013i 0.0008 + 0.0018i 0.0017 + 0.0029i -0.0017 - 0.0030i -0.0012 - 0.0024i 0.0012 + 0.0023i -0.0008 - 0.0018i 0.0004 + 0.0014i 0.0014 + 0.0026i -0.0014 - 0.0026i 0.0016 + 0.0029i -0.0015 - 0.0028i 0.0006 + 0.0016i -0.0005 - 0.0016i -0.0031 - 0.0053i 0.0021 + 0.0035i 0.0012 + 0.0023i -0.0011 - 0.0023i 0.0031 + 0.0052i -0.0021 - 0.0035i 0.0018 + 0.0030i -0.0014 - 0.0026i -0.0004 - 0.0014i 0.0003 + 0.0013i 0.0010 + 0.0021i -0.0010 - 0.0021i 0.0447 + 0.0790i 0.0494 + 0.0883i 0.0031 + 0.0053i 0.0135 + 0.0228i 0.0173 + 0.0294i 0.0422 + 0.0741i 0.0651 + 0.1251i 0.0665 + 0.1303i 0.0556 + 0.1011i 0.0516 + 0.0927i 0.0366 + 0.0638i 0.0241 + 0.0413i 0.0574 + 0.1050i 0.0605 + 0.1124i 0.0674 + 0.1412i 0.0670 + 0.1329i 0.0642 + 0.1221i 0.0619 + 0.1158i 0.0275 + 0.0471i 0.0338 + 0.0584i 0.0556 + 0.1011i 0.0516 + 0.0927i 0.0674 + 0.1412i 0.0670 + 0.1329i 0.0665 + 0.1303i 0.0574 + 0.1050i 0.0241 + 0.0413i 0.0173 + 0.0294i 0.0447 + 0.0790i 0.0494 + 0.0883i 0.0605 + 0.1124i 0.0651 + 0.1251i 0.0422 + 0.0741i 0.0366 + 0.0638i 0.0275 + 0.0471i 0.0338 + 0.0584i 0.0619 + 0.1158i 0.0642 + 0.1221i 0.0031 + 0.0053i 0.0135 + 0.0228i 0.0447 + 0.0790i 0.0495 + 0.0883i 0.0031 + 0.0052i 0.0135 + 0.0228i 0.0173 + 0.0293i 0.0422 + 0.0740i 0.0651 + 0.1251i 0.0665 + 0.1303i 0.0556 + 0.1011i 0.0516 + 0.0927i ```

Create a microstrip patch antenna with a FR4 dielectric substrate.

```d = dielectric('FR4'); pm = patchMicrostrip(Length=75e-3,Width=37e-3,... GroundPlaneLength=120e-3,GroundPlaneWidth=120e-3,... Substrate=d)```
```pm = patchMicrostrip with properties: Length: 0.0750 Width: 0.0370 Height: 0.0060 Substrate: [1x1 dielectric] GroundPlaneLength: 0.1200 GroundPlaneWidth: 0.1200 PatchCenterOffset: [0 0] FeedOffset: [-0.0187 0] Conductor: [1x1 metal] Tilt: 0 TiltAxis: [1 0 0] Load: [1x1 lumpedElement] ```
`show(pm)`

Plot the current distribution on the antenna at a frequency of 1.67 GHz.

```figure current(pm,1.67e9,'dielectric')```

Create a default pifa (planar inverted F antenna).

`ant = pifa;`

Visualize the current distribution on the pifa antenna using log function scale.

`current(ant,1.75e9,Scale="log")`

Create Minkowski's island fractal antenna with an FR4 dielectric substrate. Plot the current distribution of the antenna at 1 GHz with the `'Slicer'` argument set to `'on'`.

```ant = fractalIsland(Substrate=dielectric('FR4')); show(ant)```

`current(ant,1e9,Slicer="on",Scale="log10")`

Select Enable slicer Mode. Then select a plane for the slice under Orientation.

Click on the plot and select a region to hide.

Click Hide Selected Region to view the desired slice.

## Input Arguments

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Antenna or array object, specified as a scalar.

Frequency to calculate current distribution, specified as a scalar in Hz.

Example: 70e6

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.

Example: `Scale="log10"`

Layer to plot the current distribution, specified as either `"metal"` or `"dielectric"`. Use this argument to choose between metal and dielectric layers and plot the current distribution at the chosen layer.

Example: `Region="dielectric"`

Data Types: `string`

Scale of the current distribution plot to visualize the current distribution on the surface of the antenna, specified as a string or a logarithmic function. The default scale is `"linear"`.

Example: `Scale="log10"`

Data Types: `string` | `function`

Option to enable or disable plot interactivity, specified as `"on"` or `"off"`, or as numeric or logical `1(true)` or `0(false)`. Set this argument to `1` or `"on"` to open the plot with the slicer panel, and to slice and view the desired cross section of the plot along the xy-, yz-, and xz- planes. Set this argument to `0` or `"off"` to open the plot without the slicer panel.

Data Types: `string` | `logical`

Type of the current distribution plot, specified as `"absolute"`, `"real"`, or `"imaginary"`. The default type is `"absolute"`. Use this name-value argument to choose between absolute, real, and imaginary values of the current against which to plot the current distribution.

Example: `Type="imaginary"`

Data Types: `string`

Option to display the direction of the current vector, specified as `"on"` or `"off"`. To display the direction of the current vector on the current distribution plot, specify this argument as `"on"`. Otherwise, specify this argument as `"off"`.

Example: `Direction="on"`

Data Types: `string`

## Output Arguments

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x, y, z components of the current distribution, returned as a 3-by-n complex matrix in A/m. The value of the current is calculated on every triangle mesh or every dielectric tetrahedron face on the surface of an antenna or array.

Cartesian coordinates representing the center of each triangle in the mesh, returned as a 3-by-n real matrix.

## Version History

Introduced in R2015a