A Polarization Reconfigurable Low-Profile Ultrawideband VHF/UHF Airborne Array for Fine-Resolution Sounding of Polar Ice Sheets

A polarization-reconfigurable low-profile ultrawideband VHF/UHF antenna array is presented in this paper. The design is based on resistively loaded planar dipole antenna elements backed with a ground plane. The antenna array has two mechanically field-switchable polarization configurations which are designed to measure the crystal orientation of ice sheets. The nominal operating mode of the array is in the vertically polarized configuration with operating frequency ranges from 150 to 550 MHz. The planar dimension of the array is 3.6 m × 0.8 m with a ground plane height of 16 cm (0.08λ_low, f_low = 150 MHz). Anechoic chamber measurements show that the array performance is in very good agreement with simulated results, for both VSWR and array radiation pattern. It is also shown that the array is capable of handling 1-kW peak power per transmit channel. The antenna array is housed within a flight-qualified composite S2-glass/epoxy fairing and can readily be mounted on airborne platforms, such as Basler BT-67 and Twin Otter, for radar sounding of polar ice sheets and glaciers.