An airborne VHF printed monopole antenna for platform constrained applications

Abstract

Major challenges faced by airborne VHF monopole antennas are to achieve wideband characteristics in permissible antenna height and to find the apt location for mounting, so as to satisfy sufficient ground plane around its feed point. The increased applications of electromagnetic spectrum result in a large number of antennas competing in the limited space available on platform. The asymmetries and curved surfaces on the platform as well as the limited size of the available ground plane may result in an insufficient ground plane for these antennas on platform. The deficient ground plane can deteriorate the radiation characteristics of antenna. Printed monopole antenna, which does not require a backing ground plane, can overcome this deficiency, as the ground planes of these antennas are implemented in the same plane as that of the radiating element. This paper proposes a wideband printed monopole VHF antenna for airborne applications which simultaneously achieves reduced height and reduced ground plane on platform. The antenna has a size of 0.1045λ×0.1272λ×0.072λ, where λ is the free space wavelength at lowest frequency of operation, and it achieves a 3: 1 VSWR bandwidth of 38%. The radiation characteristics and size of the proposed antenna are comparable to the conventional airborne blade monopole antenna with the added advantage of requiring minimal ground plane to mount on.