# ARTS built-in documentation server

## Workspace Method antenna_responseGaussianEffectiveSize

### Description

Sets up Gaussian antenna responses.
Similar to antenna_responseGaussianConstant but allows to set up
responses that varies with frequency. That is, the method assumes
that the response is the same for all polarisations, and that it
can be modelled as a Gaussian function varying with frequency.
The full width at half maximum (FWHM in radians) is calculated as:
fwhm = lambda / leff
where lambda is the wavelength and *leff* is the effective size of
the antenna. Normally, *leff* is smaller than the physical antenna
size.
Antenna responses are created for *nf* frequencies spanning the
range [*fstart*,*fstop*], with a logarithmic spacing. That is, the
frequency grid of the responses is taken from VectorNLogSpace.
The responses have a common angular grid. The parameters to define
the grid are the same as for antenna_responseGaussianConstant. If
*grid_width* is <= 0, it is set to twice the FWHM at the lowest
frequency.

**Authors: **Patrick Eriksson

### Synopsis

antenna_responseGaussianEffectiveSize( | antenna_response, leff, grid_width, grid_npoints, nf, fstart, fstop, do_2d ) |

### Variables

OUT | antenna_response | (GriddedField4) | The antenna pattern/response. |

GIN | leff | (Numeric) | Effective size of the antenna, |

GIN | grid_width | (Numeric, Default: -1.0) | Full width of grid. |

GIN | grid_npoints | (Index, Default: 21) | Number of points to represent the grid. |

GIN | nf | (Index) | Number of points in frequency grid (must be >= 2) |

GIN | fstart | (Numeric) | Start point of frequency grid |

GIN | fstop | (Numeric) | End point of frequency grid |

GIN | do_2d | (Index, Default: 0) | Set to 1 to create a 2D antenna pattern. |