Calculate radar beam width

Calculates the width of a radar beam as a function of range and beam angle.

Usage

beam_width(range, beam_angle = 1, path = "two_way")

Arguments

range

Numeric. Range, i.e. distance from the radar antenna, in m.

beam_angle

Numeric. Beam opening angle in degrees, typically speciefied as the angle between the half-power (-3 dB) points of the main lobe for the one-way antenna pattern.

path

Character. One of two_way (default) or one_way for specifying the effective beam width for the radar's antenna pattern as it transmits a signal (one_way), or as it transmits and receives a signal (two_way).

Value

numeric. Beam width in m, typically the full width at half maximum (FWHM).

Details

The two-way beam is effectively narrower than the one-way beam because the power distribution is squared in the two-way path (transmit and receive). Using the normal approximation for the beam power profile, this means the two-way beam width equals the one-way beam width divided by sqrt(2).

See also

Other beam_functions: beam_distance(), beam_height(), beam_profile(), beam_profile_overlap(), beam_range(), gaussian_beam_profile()

Examples

#' # Beam width in meters at 10 km range:
beam_width(10000)
#> [1] 123.4103

# Define ranges from 0 to 1000000 m (100 km), in steps of 100 m:
range <- seq(0, 100000, 100)

# Plot the two-way beam width as a function of range:
plot(range, beam_width(range), ylab = "two-way beam width [m]", xlab = "range [m]")


#' # Plot the one-way beam width as a function of range:
plot(range, beam_width(range), ylab = "one-way beam width [m]", xlab = "range [m]")