Recent studies investigated square-complementary waveforms for sidelobe suppression in radar. Targets were assumed to have a constant radar cross section (RCS). However, complex targets exhibit a RCS that varies wildly with frequency. This study reviews the necessity of a constant RCS, particularly for targets composed of isotropic point reflectors. The source of variable RCS is shown to manifest as cross terms in complementary processing output. Cross terms are mitigated by increasing frequency over a pulse train and performing Doppler processing, improving performance.