Planar Wideband Phased-Array Element For VHF RADAR

Currently fielded VHF FOPEN SAR systems are tailored around large Unmanned Aerial Vehicles such as the Global Hawk platform. The current antenna design is an array of log-periodic monopoles that is permanently installed on the platform. While these antennas deliver the gain and suppress the backlobe at sufficient level, they are large and require permanent installation on the aircraft. There is a need to provide an alternate technology that does not require a permanent installation on a large aircraft. Installation on tactical sized UAVs such as Predator is desired for maximizing the tactical value and flexibility of the system. The FIRST RF solution achieves the critical performance characteristics from a low profile two element array. Many wideband array elements are 3 dimensional and require a minimum spacing of 0.2 wavelengths or more of depth. This is impractical for VHF frequencies on small platforms. The proposed array element technology is capable of meeting coverage and bandwidth requirements while maintaining conformality. In addition, traditional array solutions require a large number of elements to achieve the necessary front to back ratio. The FIRST RF beamforming technology requires a minimum of only 2 elements to achieve the front to back requirement.