# efficiency

Since R2021a

## Description

example

E = efficiency(object,frequency) returns the radiation efficiency of the antenna or array over the specified frequency.

example

efficiency(object,frequency) plots the radiation efficiency of the antenna or array over the specified frequency.

E = efficiency(___,UseParallel = true) uses the Parallel Computing Toolbox™ to perform efficiency calculations for each frequency in parallel. To use this feature, you need a license to the Parallel Computing Toolbox.

## Examples

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Create a top-hat monopole antenna.

ant = monopoleTopHat(Conductor=m);
show(ant)

Plot the radiation efficiency of the antenna over a frequency range of 40-100 MHz.

efficiency(ant,linspace(40e6,100e6,41))

Create and visualize patch microstrip antennas with PEC, copper, silver, and aluminium metal patches.

ant_patchPEC = patchMicrostrip(Substrate=dielectric("Air"),Conductor=metal("PEC"));
ant_patchCopper = patchMicrostrip(Substrate=dielectric("FR4"),Conductor=metal("Copper"));
ant_patchSilver = patchMicrostrip(Substrate=dielectric("FR4"),Conductor=metal("Silver"));
ant_patchAluminium = patchMicrostrip(Substrate=dielectric("FR4"),Conductor=metal("Aluminium"));

Compare the radiation efficiency of these antennas at the frequency of 1 GHz.

Eff_patchPEC = efficiency(ant_patchPEC,1e09)
Eff_patchPEC = 1
Eff_patchCopper = efficiency(ant_patchCopper,1e09)
Eff_patchCopper = 0.4663
Eff_patchSilver = efficiency(ant_patchSilver,1e09)
Eff_patchSilver = 0.4109
Eff_patchAluminium = efficiency(ant_patchAluminium,1e09)
Eff_patchAluminium = 0.4644

## Input Arguments

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Antenna or array to calculate the efficiency, specified as an antenna or array from the catalog, a pcbStack object, an installedAntenna object, or custom antenna or array created using either of these:

Note

Only homogeneous arrays are supported for efficiency calculation, with an exception of conformalArray.

Frequency or frequency range over which to calculate the radiation efficiency, specified as a scalar or a vector in Hz.

Example: 50e6:1e6:100e6

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 efficiency calculations at multiple frequencies for computationally large antennas and arrays.

Example: UseParallel=true

Data Types: logical

## Output Arguments

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Radiation efficiency of the antenna, returned as a scalar or a vector with values in the range [0,1].

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The time-average power density radiated by an antenna is:

where, r = radius of the sphere,

θ, φ = spherical coordinate angles,

E, H = electric and magnetic field intensity respectively.

The total power radiated by antenna is:

where, U = radiation intensity (W/ unit solid angle),

dΩ = element of solid angle.

The radiation efficiency is given as:

where, Pin = total input power.

## Version History

Introduced in R2021a