The paper describes a multi-domain CAD platform, exploiting nonlinear and electromagnetic software tools, for the rigorous analysis of time-modulated linear arrays. A circuit-level analysis of the non-radiating network including the time-modulated nonlinear switches is carried out by means of the Harmonic-Balance (HB) method. The corresponding nonlinear regime is then used to evaluate the actual far-field radiated by the array in the real operating conditions. Examples with different switch modulation patterns are presented in order to demonstrate the effectiveness of the tool and also the impact of simplifying assumptions typical of previous approaches.