COMPACT PRINTED MONOPOLE ANTENNA FOR AIRBORNE APPLICATIONS

A compact printed wideband antenna operating in VHF band with simple geometry and nearly omnidirectional radiation characteristics is presented for airborne applications. The monopole antennas used in VHF airborne communications have height constraints as well as ground plane size constraints. This Letter proposes a printed monopole antenna with very compact size for airborne application which overcomes the ground plane size constraints of monopole antennas. The size of the proposed antenna is 0.063λ0 X 0.118λ0, and the ground plane size is 0.025 λ0 X 0.132 λ0 where λ0 is the free space wavelength at lowest frequency of operation. The antenna achieves a height reduction of 75% compared to a conventional quarter wave monopole antenna. It also exhibits a 3:1 VSWR bandwidth of 32% in VHF band.