Abstract: Based on the traditional moment of method (MOM), a method combined with the physical optics (PO), namely MOM-PO, is described in detail. An iterative method from the combination of the electrical-field integral equation (EFIE) and the magnetic-field integral equation (MFIE), so called HEMI, is also introduced. The three presented methods are compared in physical mechanism, calculating costly and numerical precision. Numerical examples validate the corresponding analyses well. The input impedance and the radiation pattern results of the HEMI agree well with those obtained using MOM. The computing time can be saved to a large extent. Although the MOM-PO method remarkably excels the other two in computing time and memory cost, it gives relatively poor precision results for electrically small problem cases, especially in the radiation patterns. For small cases, MOM-PO produces obvious errors in the main, the side and the back lobes.