Low-profile, Wideband Antennas for the Joint Tactical Radio System (JTRS)

The purpose of the proposed program is to design, fabricate, and demonstrate a prototype wideband antenna that is operational over selected portions of the service bands (2-2000 MHz) required by the Joint Tactical Radio System (JTRS). In addition, the designs will address the following technical objectives: (1) minimize the voltage-standing-wave ratio (VSWR) with a target VSWR of 2.0, (2) maximize the radiation efficiency, (3) demonstrate an omni-directional radiation pattern in the azimuth plane, and (4) exhibit an elevation pattern that is equivalent to that of a quarter-wavelength monopole for line of sight waveforms. In addition to the above criteria, the antenna will be low profile for improved aerodynamics. In particular, aircraft platforms typically mount antennas a distance of one-quarter wavelength above the ground plane to provide maximum broadside gain by constructively adding the primary and reflected antenna signals. If the distance is less than one-quarter wavelength, the primary and reflected signals will partially or completely cancel each other, thus limiting the bandwidth of the antenna. This effort will investigate and demonstrate novel approaches to overcoming the bandwidth limitations associated with wideband, low-profile antennas including, but not limited to, the use of magnetically conducting ground planes.