MAPRad - A miniaturised magnetic antenna Ground Penetrating Radar

With increased interest in missions to the Moon and Mars aimed at permanent human presence, exploration and detection of key subsurface structures and resources is crucial. Current scientific missions to the Moon and Mars have been in the form of orbital sounding radars and surface rover-based ground penetrating radar (GPR). Orbital sounding radars often have lower resonant frequencies with lower depth resolution but higher penetration power (Kobayashi et al., 2014; Putzig et al., 2023), while rover based GPR have comparatively higher resonant frequencies which trade the better depth resolution for lower penetration depth (Putzig et al., 2023; Lai et al., 2020). To date only electric field-based antennae have been used in these applications, which are restricted in their size being fractional powers of two of their resonant wavelengths. Our project has been to design, manufacture and test a miniaturised magnetic antenna for use in a GPR system, called MAPRad. MAPRad utilizes a pair of ferromagnetic cored coil antennae designed for use at a resonant frequency of 20 MHz with a core length of 30 cm. Comparing this to an equivalent electric field half wave dipole, which would be 7.5m long, the antenna is 25 times smaller, while also possessing an increased bandwidth. The saving in space would allow for a rover mounted GPR system to operate at a significantly lower central frequency and across a wider band as compared to traditional electric field antennae, allowing for a greater depth penetration while retaining resolution. The current MAPRad prototype has been field tested and validated using the magnetic antennae receiver and an electric transmitter. Data suggests that MAPRad has very similar detection characteristics as an equivalent electric field antenna system. The next phases of the project involve implementing the magnetic transmitter and field testing the system with both magnetic antenna on the transmitter and receiver.