# current

Current distribution on metal or dielectric antenna or array surface

## Syntax

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

## Description

example

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

example

````i = current(object,frequency)` returns the x, y, z components of the current on the surface of an antenna or array object, at a specified frequency.```
````[i,p] = current(object,frequency)` returns the x, y, z components of the current on the surface of an antenna or array object, at a specified frequency and at the point in which the current calculation is performed.```

example

````current(object,frequency,'dielectric')` calculates and plots the absolute value of current at a specified frequency value on the dielectric face of the antenna or array.```
````i = current(object,frequency,'dielectric')` returns the x, y, z components of the current on the dielectric surface of an antenna or array object, at a specified frequency.```
````i = current(___,Name,Value)` calculates the current on the surface of an antenna using additional name-value pairs.```

## 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 0.0009 + 0.0020i 0.0013 + 0.0025i -0.0002 - 0.0012i 0.0003 + 0.0014i 0.0005 + 0.0015i -0.0005 - 0.0015i -0.0013 - 0.0025i -0.0010 - 0.0020i 0.0015 + 0.0028i -0.0015 - 0.0028i -0.0012 - 0.0023i 0.0011 + 0.0023i 0.0030 + 0.0052i -0.0021 - 0.0035i 0.0017 + 0.0030i -0.0017 - 0.0030i -0.0007 - 0.0018i 0.0007 + 0.0017i -0.0000 - 0.0041i 0.0000 + 0.0021i 0.0007 + 0.0017i -0.0007 - 0.0018i 0.0005 + 0.0015i -0.0005 - 0.0015i 0.0011 + 0.0022i 0.0003 + 0.0013i -0.0009 - 0.0020i 0.0009 + 0.0020i -0.0015 - 0.0027i 0.0016 + 0.0028i -0.0002 - 0.0012i -0.0011 - 0.0023i 0.0001 + 0.0021i -0.0000 - 0.0041i -0.0031 - 0.0052i 0.0021 + 0.0035i -0.0017 - 0.0030i -0.0013 - 0.0025i 0.0017 + 0.0030i 0.0014 + 0.0025i 0.0009 + 0.0020i 0.0013 + 0.0025i -0.0002 - 0.0012i 0.0003 + 0.0013i 0.0005 + 0.0015i -0.0005 - 0.0015i -0.0013 - 0.0025i -0.0009 - 0.0020i 0.0016 + 0.0028i -0.0015 - 0.0028i 0.0569 + 0.1044i 0.0434 + 0.0768i 0.0667 + 0.1338i 0.0656 + 0.1283i 0.0649 + 0.1254i 0.0629 + 0.1191i 0.0379 + 0.0663i 0.0530 + 0.0959i 0.0349 + 0.0607i 0.0284 + 0.0490i 0.0460 + 0.0818i 0.0508 + 0.0914i 0.0032 + 0.0054i 0.0139 + 0.0236i 0.0179 + 0.0304i 0.0250 + 0.0430i 0.0586 + 0.1083i 0.0616 + 0.1156i 0.0670 + 0.1426i 0.0670 + 0.1362i 0.0616 + 0.1158i 0.0586 + 0.1084i 0.0629 + 0.1192i 0.0650 + 0.1255i 0.0509 + 0.0915i 0.0657 + 0.1285i 0.0530 + 0.0960i 0.0569 + 0.1044i 0.0349 + 0.0608i 0.0286 + 0.0493i 0.0667 + 0.1338i 0.0461 + 0.0820i 0.0670 + 0.1362i 0.0670 + 0.1426i 0.0032 + 0.0055i 0.0140 + 0.0238i 0.0252 + 0.0432i 0.0379 + 0.0663i 0.0180 + 0.0306i 0.0435 + 0.0770i 0.0569 + 0.1044i 0.0434 + 0.0768i 0.0667 + 0.1338i 0.0656 + 0.1283i 0.0648 + 0.1254i 0.0628 + 0.1191i 0.0379 + 0.0663i 0.0530 + 0.0959i 0.0349 + 0.0607i 0.0284 + 0.0490i ```

Create a microstrip patch antenna using 'FR4' as the 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 in 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 1GHz with the `'Slicer'` argument set to `'on'`.

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

Scale to visualize the current distribution on the surface of the antenna, specified as a string or a function. The string values are: `'linear'`, `'log'`, `'log10'`. By default, the value is `'linear'`. The function can be of any mathematical function such as `log`, `log10`, `cos`, or `sin`.

Data Types: `char` | `function`

Flag to enable or disable plot interactivity, specified as `'on'` or `'off'`, or as numeric or logical `1(true)` or `0(false)`. Setting this flag to `1` or `'on'` opens a plot with the Slicer panel, where you can slice and view the desired cross section of the plot along the XY-, YZ-, and XZ- planes. Setting this flag to `0` or `'off'` opens a plot without the Slicer panel.

Data Types: `string` | `logical`

## Output Arguments

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x, y, z components of 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