Target Gain Factor Calculator

What is the target gain factor?

In a radar system, an electromagnetic signal is radiated out from a transmitting antenna in a target/object’s direction. Now, the target reflects (some power absorbed) the electromagnetic signal back to the radar system. Then, the receiving antenna of the radar system receives the echo signal from the target for further processing; to detect the object's location and velocity. 

Target gain factor

The target gain factor represents the strength of the reflected signal (in dB) from the target/object in the radar receiver direction when compared with a perfectly smooth sphere radiator (i.e., isotropic radiator). An isotropic radiator (theoretical point source of electromagnetic wave) that would radiate out waves equally in all directions with the same intensity.

The target gain factor depends on the RCS (in m2) (i.e., object size seen by the radar) and the frequency of the radar signal. If the target has a large RCS, the target gain factor will be high. Thus, a high gain factor represents the strength of the electromagnetic waves getting reflected perfectly in the direction of the radar receiver. 

The Target Gain Factor (Gσ) is also called by various names such as Gain of RCS or Equivalent Gain of RCS or Gain of Target Cross Section or Gain-sub- Sigma.

How to calculate the target gain factor?

The formula used to calculate the target gain factor is given below:

The formula can be written in another form:

Where,

Gσ = Target gain factor in dB (decibels)

σ = Radar Cross-section or Scattering co-efficient of target in m2

λ = Wavelength in m/nm/µm/Angstrom

f = frequency in MHz/GHz