In this paper, the principle of the wave concept iterative procedure (WCIP) are described. The spatial diffraction operation is concluded in coaxial probe feed conditions. The transverse electric field and current density distribution of slot-loaded H-shaped dual-frequency antenna surface are simulated by the WCIP. Besides, the return loss of the antenna is analyzed. The numerical results show a good agreement compared with the references, which illustrates the correctness and efficiency of the WCIP.