Abstract <p>Sound field and radiation impedance are crucial acoustic performance parameters. Sound field calculation concerns sound propagation from a source and pertains to practical application problems within a specific environment. In contrast, radiation impedance is associated with the matching of the radiating elements with a circuit. Free boundary stepped radiators with high directional properties have significant application potential in the field of high-power gas medium ultrasonics. This study proposes a simulation for the computational estimation of the radiation field and impedance of stepped radiators based on the Rayleigh method. The axial sound pressure and directivity of the rectangular stepped radiator are calculated theoretically. At the same time, the radiation impedance is calculated. The results of the sound field test and radiation impedance calculations verified the validity of the proposed method. Thus, a practical and efficient approach to the analysis of the acoustic performance of arbitrary sound radiator was realized. The proposed method offers valuable insights and addresses a crucial gap in understanding these parameters for diverse radiator configurations<i>.</i></p>