HF Wire-Mesh Dipole Antennas for Broadband Ice-Penetrating Radar

Abstract

A novel high frequency (HF) to very high frequency (VHF) wire-mesh dipole antenna design for use in polar regions is discussed and evaluated. The antenna was designed to be lightweight, readily demountable, and acceptably robust. This is an initial step in the development of a ground-based, phasesensitive, synthetic aperture imaging system for use on an autonomous rover platform. The results of initial trials on the Rhône Glacier, Switzerland in August 2019 are discussed, with particular attention being paid to the effect on antenna performance of high surface water content. Including the effects of surface water resulted in good agreement between field results and modelled performance.

Design of an HF-VHF Ice Penetrating Synthetic Aperture Radar

“…Nansen sledges are commonly available in polar research stations and have been used as the intended mount for the antenna. A simulation model of the wire-mesh dipole, a typical 3 m sledge and 10 mm thick twin-wall polycarbonate support structure was created in SIMULIA CST Studio 2020 to determine the expected impedance and radiation pattern, which are comparable to previously reported values [14].…”

“…The antennas for the HF-VHF ApRES use the broadband wire-mesh dipole design [14] with a new matching network. This has been redesigned to improve the bandwidth and allow for the option of mounting the antennas on sledges to facilitate rover-driven SAR deployment in a polar environment.…”

“…This increases the required spatial sampling interval to 1 m [13] which allows SAR surveys to be conducted across wider areas, at the cost of reduced vertical resolution (Δ𝑅) of 4.19 m in ice and increased antenna size. Wire-mesh dipole antennas [14] with improved matching are realised to retain a lightweight platform that meets the payload limit of polar rovers. Laboratory-based testing of the HF-VHF radar printed circuit board (PCB) and an outdoor measurement of the antennas are presented.…”

Near‐high frequency antenna for unmanned aerial system ice‐penetrating radar

“…Using a technique similar to that described in ref. [26], the LC networks were converted into balanced configurations followed by a 1:1 balun. In both cases, the balun is a commercially off‐the‐shelf wideband 1:1 RF transformer in surface mount package (Coilcraft PWB1010‐1L), and it has a measured insertion loss of <0.5 dB over the 30–45 MHz range.…”

Towards a Field-Ready HF-VHF Ground-Based Ice Penetrating Synthetic Aperture Radar: Forward Modelling and Validation for SAR Imaging

“…Extending the Finite Difference Time Domain (FDTD) simulation domain to the length of the model geometry would result in excessive simulation times, particularly in the terrace and channel models. Instead, models of the HF ApRES wire-mesh antennas [14] are positioned in the centre of the x-y plane and the basal geometry is shifted along the x axis of a fixed simulation domain with dimensions of 100 m in each cardinal direction. Data acquisition mimics that of a stepped frequency radar with antennas orientated with the dipole axis in the x-axis.…”