# ARTS built-in documentation server

## Workspace Method antenna_responseVaryingGaussian

### Description

```Sets up gaussian antenna responses.

Similar to antenna_responseGaussian 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 width, determined by
*xwidth_si*, is set for the lowest frequency, while the spacing
(*dx_si*) is set for the highest frequency. This ensures that both
the width and spacing are equal or better than *xwidth_si* and
*dx_si*, respectively, for all frequencies.

If the 2D option is selected (*do_2d*), a circular antenna is
assumed and the response is any direction follows the 1D case.

The antenna repsonse is not normalised.

```

Authors: Patrick Eriksson

### Synopsis

 antenna_responseVaryingGaussian( antenna_response, leff, xwidth_si, dx_si, nf, fstart, fstop, do_2d )

### Variables

 OUT antenna_response (GriddedField4) The antenna pattern/response. GIN leff (Numeric) Effective size of the antenna GIN xwidth_si (Numeric, Default: 3) Half-width of response, in terms of std. dev. GIN dx_si (Numeric, Default: 0.1) Grid spacing, in terms of std. dev. 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.