Systems and methods provide a HESA (“High Efficiency Sensitivity Accuracy”) direction-finding (“DF”) antenna system that operates over a range from 2 MHz to 18 GHz. The system may include components such as a dipole array, a monopole array, and an edge-radiating antenna, each component being responsive to a specific frequency range. The system may further include biconical flares that optimally terminate a freespace wave in a small aperture.