Abstract: Disclosed is an Radio Frequency (RF) volumetric direction finding (DF) methodology, utilizing an Half Maxwell Fish-eye (HMFE) Lens having a semi-spherical shape, a focal plane with a feed structure composed of near-equally spaced frequency-independent antenna elements disposed uniformly to form a 2-dimentional feed array; and RF power splitters for each element and combiners for combining the RF energy received by the elements; forming rows and columns; thereby reducing the number of required RF receiver channels for subsequent processing, where the maximum row/column and differential amplitude comparison is used for deriving DF estimation of intercepted signals; as part of a robust signal detection and direction-finding (DF) system; for detecting and processing a plurality of signals emanating from navigation, radar and communication equipment on surface and airborne platforms.

Abstract: Disclosed is an Radio Frequency (RF) receiving system methodology, utilizing an Luneberg Lens having a spherically shaped outer surface and a semi-spherical shaped focal surface composed of near-equally spaced frequency-independent antenna elements disposed uniformly to cover the semi-spherical focal surface of the Luneberg Lens; and radio frequency (RF) power splitters and combiners for combining the RF energy received by the antenna elements; forming rows and columns; thereby reducing the number of required RF receiver channels for subsequent processing, where the maximum row/column and differential amplitude comparison is used for deriving volumetric direction finding (DF) of intercepted signals; as part of a robust signal detection and direction-finding (DF) system; for detecting and processing a plurality of signals emanating from surface and airborne platforms within the hemisphere, where each surface and airborne platform include transmitters for transmitting navigation, communication and radar signals