Calculation of radar cross section for an active array

Considers an active array antenna consisting of open ended waveguide elements, fed individually by active transmit/receive modules. Such an array may be required to operate in environments where other radars are attempting to locate it. These other radars could be aboard hostile ships or homing missiles. The way in which the active array scatters incident waves (its radar cross section) is therefore of considerable importance. A method developed for calculating the RCS of an array of open ended waveguides is described. The RCS considered is monostatic: only the reflected energy propagating back in the incidence direction is evaluated. This is the energy actually received by an observing radar. It is important to bear in mind that a monostatic RCS pattern is not equivalent to a far field pattern in that the `area under the curve´ does not correspond to total scattered power as it does with a far field pattern. The theory is compared with results from RCS measurements of a test array and shown to be in good agreement