Low Profile, Very Wide Bandwidth Aircraft Communications Antennas Using Advanced Ground-Plane Techniques

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.