Regarding complex rcs in rcs() function in Antenna Toolbox

Hello,

In the Antenna Toolbox, a function named rcs computes the RCS from an object.

Since there is an option to obtain the complex RCS, it would mean that a receiver would have to be located at a distance from scene centre to obtain meaningful phase data.

My question is, at what distance is the receiver positioned from the scene center to receive the scattered field?

Thank you.

[Yue Feng Tan]

Hi all,

I think I've found it, in the rcs() function of MATLAB.

For objects that have electrical length , the far field distance is .

In case anyone has doubts about this in the future :)

Answer 1

[Vinod Dwarapudi]

Hi Yue Feng Tan

The receiver is placed on a far-field sphere centered on the target. The sphere radius is 100λ at the lowest frequency.

For linear RCS, the result is independent of range once the far-field condition is satisfied.

For complex RCS also, the magnitude is range-independent in the far field. But the phase contains a propagation term proportional to e^−jkR, where R is the receiver distance from the scene center. Consequently, changing the observation radius changes the phase but not the magnitude.