drift.telescope.cylbeam
Functions
|
Beam amplitude across the sky. |
|
Beam for a dipole above a ground plane. |
|
Beam amplitude across the sky for the X dipole (points E). |
|
Beam amplitude across the sky for the Y dipole (points N). |
|
Calculate the Fraunhofer diffraction pattern for a feed illuminating a cylinder (in 1D). |
|
Calculate the unit polarisation vectors at each position on the sphere for a dipole direction. |
- drift.telescope.cylbeam.beam_amp(angpos, zenith, width, fwhm_x, fwhm_y, rot=[0.0, 0.0, 0.0])
Beam amplitude across the sky.
- Parameters:
angpos (np.ndarray[npoints]) – Angular position on the sky.
zenith (np.ndarray[2]) – Position of zenith on spherical polars.
width (scalar) – Cylinder width in wavelengths.
fwhm_x (scalar) – Full with at half power in the x and y directions.
fwhm_y (scalar) – Full with at half power in the x and y directions.
rot ([yaw, pitch, roll]) – Rotation to apply to cylinder in yaw, pitch and roll from North.
- Returns:
beam – Amplitude of beam at each point.
- Return type:
np.ndarray[npoints]
- drift.telescope.cylbeam.beam_dipole(theta, phi, squint)
Beam for a dipole above a ground plane.
- drift.telescope.cylbeam.beam_x(angpos, zenith, width, fwhm_e, fwhm_h, rot=[0.0, 0.0, 0.0])
Beam amplitude across the sky for the X dipole (points E).
Using ExpTan model.
- Parameters:
angpos (np.ndarray[npoints, 2]) – Angular position on the sky.
zenith (np.ndarray[2]) – Position of zenith in spherical polars.
width (scalar) – Cylinder width in wavelengths.
fwhm_e – Full with at half power in the E and H planes of the antenna.
fwhm_h – Full with at half power in the E and H planes of the antenna.
rot ([yaw, pitch, roll]) – Rotation to apply to cylinder in yaw, pitch and roll from North.
- Returns:
beam – Amplitude vector of beam at each point (in thetahat, phihat)
- Return type:
np.ndarray[npoints, 2]
- drift.telescope.cylbeam.beam_y(angpos, zenith, width, fwhm_e, fwhm_h, rot=[0.0, 0.0, 0.0])
Beam amplitude across the sky for the Y dipole (points N).
Using ExpTan model.
- Parameters:
angpos (np.ndarray[npoints, 2]) – Angular position on the sky.
zenith (np.ndarray[2]) – Position of zenith in spherical polars.
width (scalar) – Cylinder width in wavelengths.
fwhm_e – Full with at half power in the E and H planes of the antenna.
fwhm_h – Full with at half power in the E and H planes of the antenna.
- Returns:
beam – Amplitude vector of beam at each point (in thetahat, phihat)
- Return type:
np.ndarray[npoints, 2]
- drift.telescope.cylbeam.fraunhofer_cylinder(antenna_func, width, res=1.0)
Calculate the Fraunhofer diffraction pattern for a feed illuminating a cylinder (in 1D).
- Parameters:
antenna_func (function(sintheta) -> amplitude) – Function describing the antenna amplitude pattern as a function of sin(angle).
width (scalar) – Cylinder width in wavelengths.
res (scalar, optional) – Resolution boost factor (default is 1.0)
- Returns:
beam – The beam pattern, normalised to have unit maximum.
- Return type:
function(sintheta) -> amplitude
- drift.telescope.cylbeam.polpattern(angpos, dipole)
Calculate the unit polarisation vectors at each position on the sphere for a dipole direction.
- Parameters:
angpos (np.ndarray[npoints, 2]) – The positions on the sphere to calculate at.
dipole (np.ndarray[2 or 3]) – The unit vector for the dipole direction. If length is 2, assume in vector is in spherical polars, if 3 it’s cartesian.
- Returns:
vectors – Vector at each point in thetahat, phihat basis.
- Return type:
np.ndarray[npoints, 2]