Low Profile, Very Wide Bandwidth Aircraft Communications Antennas Using Advanced Ground-Plane Techniques Navy SBIR FY2011.2 Sol No.: Navy SBIR FY2011.2 Topic No.: N112-113 Topic Title: Low Profile, Very Wide Bandwidth Aircraft Communications Antennas Using Advanced Ground-Plane Techniques Proposal No.: N112-113-0141 Firm: FIRST RF CORPORATION 5340 Airport Blvd. Boulder, Colorado 80301 Contact: Benjamin Wilmhoff Phone: (303) 449-5211 Web Site: firstrf.com Abstract: While substantial progress has been made toward developing wideband, low-profile antennas, maintenance of reasonable gain at very low profiles and small diameters, especially as operating frequency is lowered, remains a problem. This is due to the fact that gain and antenna size are inversely related - an improvement in one generally means a loss in the other. To overcome this inverse relationship, FIRST RF proposes the use of low profile, reactive groundplane surfaces to create a surface wave antenna for aircraft communications. This surface wave antenna is formed through the combination of broadband driver element and a surrounding groundplane surface that, when coupled to, produces end-fire surface wave radiation. This results in improved gain performance at horizon, while reducing the profile of the antenna below that of current designs. In addition to displaying excellent performance in preliminary testing, the unique groundplane surfaces proposed for this Phase I effort are inexpensive and easy to manufacture, making them desirable for installation on aircraft. The proposed FIRST RF groundplane surfaces build upon the proven performance of conventional RF techniques to improve gain near horizon while producing a broadband, low profile antenna with far-reaching potential for use in other military and commercial applications. Benefits: Although the specific objective of this solicitation is to develop wideband, low profile antenna solutions with increased gain for aircraft communications applications, FIRST RF recognizes that the proposed technologies have considerable relevance in other aircraft, DoD, and commercial applications. Though the team anticipates wideband continuous coverage from 30 - 512 MHz, the technology is particularly useful to users of SINCGARS (30 - 88 Mhz), VHF Airband (108 - 174 MHz) and UHF-LOS (225 - 512 MHz) radios. In addition to COMMs applications, other applications benefitting from a low profile wideband antenna include ISR and Synthetic Aperture Radar (SAR). Furthermore, by increasing gain near horizon while maintaining broadband performance and a low profile, the approach allows for the consolidation of multiple functions into a single aperture. Maintaining a low profile allows for more effective use of payload space as well as larger antenna apertures on the aircraft's skin. In addition, because this design is not integrated into the airframe, existing aircraft can be retrofitted with the new designs. FIRST RF has shown the capability to transition SBIR technologies quickly and effectively to fielded hardware, so the results of this effort will be leveraged as the maturity of the technology allows. Return