# returnLoss

Return loss of antenna or scan return loss of array

## Syntax

``returnLoss(antenna,frequency)``
``returnLoss(antenna,frequency,z0)``
``rl = returnLoss(antenna,frequency,z0)``
``returnLoss(array,frequency)``
``returnLoss(array,frequency,z0,elementnumber)``
``rl = returnLoss(array,frequency,z0,elementnumber)``
``rl = returnLoss(___,UseParallel = true)``

## Description

````returnLoss(antenna,frequency)` calculates and plots the return loss of an antenna, over a specified frequency and at a reference impedance of 50 ohm.```

example

````returnLoss(antenna,frequency,z0)` calculates and plots the return loss of an antenna, over a specified frequency and a given reference impedance, `z0`.```
````rl = returnLoss(antenna,frequency,z0)` returns the return loss of an antenna.```
````returnLoss(array,frequency)` calculates the return loss of the individual array elements over the specified frequency at a reference impedance of 50 ohm and opens an interactive return loss plot. You can switch between the individual element plots by specifying the element number in the Elements box at the bottom of the plot.```
````returnLoss(array,frequency,z0,elementnumber)` calculates and plots the scan return loss of a specified antenna element in an array.```
````rl = returnLoss(array,frequency,z0,elementnumber)` returns the scan return loss of a specified antenna element in an array. ```
````rl = returnLoss(___,UseParallel = true)` uses the Parallel Computing Toolbox™ to perform return loss calculations for each frequency in parallel. To use this feature, you need a license to the Parallel Computing Toolbox.```

## Examples

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This example shows how to calculate and plot the return loss of a circular loop antenna over a frequency range of 50MHz-100MHz.

```h = loopCircular; returnLoss (h, 50e6:1e6:100e6);```

## Input Arguments

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Antenna to calculate return loss, specified as either:

Example: `dipole`

Example: `customAntennaMesh`

Example: `customAntenna`

Example: `pcbStack`

Array to calculate scan return loss, specified as either:

Example: `linearArray`

Example: `customArrayGeometry`

Example: `array(pcbStack,"linear")`

Frequency range used to calculate return loss, specified as a vector in Hz.

Example: 50e6:1e6:100e6

Data Types: `double`

Reference impedance, specified as a scalar in ohms.

Example: 40

Data Types: `double`

Antenna element number in array, specified as a scalar.

Example: `1`

Data Types: `double`

Flag to enable parallel pool, specified as a logical value. The default value is `false`. Set the flag to `true` or `1` to enable the parallel pool. Use parallel pool to speedup the return loss calculations at multiple frequencies for computationally large antennas and arrays.

Example: `UseParallel=true`

Data Types: `logical`

## Output Arguments

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Return loss of antenna or scan return loss of array, returned as a vector in dB. The return loss is calculated using the formula

`$RL=-20{\mathrm{log}}_{10}\text{ }\text{\hspace{0.17em}}|\frac{\left(Z-{Z}_{0}\right)}{\left(Z+{Z}_{0}\right)}|$`

where,

• Z = input impedance of antenna or scan impedance of array

• Z0 = reference impedance

## Version History

Introduced in R2015a