The frequency response of many antennas includes an angle-independent factor that rises in proportion to frequency. Two passes through the radar antenna and once for the ground patch as an antenna causes a rising third-order frequency dependence to be impressed upon the received data. After a review of antenna theory and types, a simulation for polar and rectangular formatted spotlight synthetic aperture radar data over two bandwidth cases, 9-10 GHz and ultra wideband 1-10 GHz, is reported. Without correction, range resolution for the first case is minimally affected but for the latter case, range resolution is seriously degraded, rectangular data being worse. Response equalizing correction restores the resolution.