Abstract: A detailed method for obtaining an accurate RCS measurement on UHF band is given by using stepped-frequency systems.Based on the stepped-frequency signal,the quasi-monostatic measurement is carried out by relying on high performance absorbers and low scattering supports and employing two log-periodic dipole antennas,and many DSP techniques are applied to reduce the error.After scaling at the Rayleigh region of a metal sphere,the indoor accurate RCS measurement is completed on UHF band.Experimental results show that the valid data can be got in the whole UHF band,and the full angular measuring error is less than ±1 dB for a metal sphere with a diameter of 15 cm.