Evaluate a 2D scattering grid from a stored TMM object

Reuses the stored T-matrix blocks to evaluate the far-field scattering response over a two-dimensional receive-angle grid at one stored frequency. This is useful for bistatic scattering maps, heatmaps, and polar-style visualizations without rebuilding the retained modal solve. In the current package build, this helper is available for the spherical and spheroidal stored branches. Stored cylinders intentionally stop at exact monostatic reuse until a validated retained cylinder angular operator is added.

Usage

tmm_scattering_grid(
  object,
  frequency = NULL,
  theta_body = NULL,
  phi_body = NULL,
  theta_scatter = NULL,
  phi_scatter = NULL,
  n_theta = 91,
  n_phi = 181
)

Arguments

object

Scatterer-object previously evaluated with target_strength(..., model = "TMM", store_t_matrix = TRUE).

frequency

Stored frequency (Hz) to evaluate. Required when the object contains more than one stored frequency.

theta_body

Incident polar angle (radians). Defaults to the stored TMM incident angle.

phi_body

Incident azimuth angle (radians). Defaults to the stored TMM incident angle.

theta_scatter

Optional vector of receive polar angles (radians). Defaults to an evenly spaced grid on [0, pi].

phi_scatter

Optional vector of receive azimuth angles (radians). Defaults to an evenly spaced grid on [0, 2*pi].

n_theta

Number of default polar-angle grid points when theta_scatter is not supplied.

n_phi

Number of default azimuth grid points when phi_scatter is not supplied.

Value

A list containing the stored frequency, the incident angles used to build the grid, the receive-angle vectors, and matrices for the complex scattering amplitude, differential scattering cross section, and its level in dB.

See also

tmm_scattering, tmm_average_orientation