Antenna design and optimisation for UHF glacial environmental sensor networks

• Main Author: Hashmi, Muhammad Abdur Rehman
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UCL (University College London) 2023
• Subjects: Antarctic; Thwaites Glacier; Antarc*; Antarctica; British Antarctic Survey
• Online Access: https://discovery.ucl.ac.uk/id/eprint/10167808/8/Hashmi_10167808_thesis_redacted.pdf; https://discovery.ucl.ac.uk/id/eprint/10167808/

Our planet’s ice masses play an important role in regulating numerous natural phenomena vital to keep our planet habitable by humans as well as other living species. Since few decades, global climate changes are probably responsible for an increased melt rate of the ice masses causing catastrophes. It is therefore desirable to monitor our planet’s ice masses for predicting catastrophes and timely initiating disaster management measures. This monitoring can also provide scientific evidence for supporting anti-climate change efforts. This research contributes to a joint UCL (University College London) – BAS (British Antarctic Survey) project that aims to develop and deploy an Environmental Sensor Network (ESN) at the Thwaites glacier, Antarctica. Glacial ESNs reported in the last two decades are reviewed, focusing on the antenna types used. A link budget framework for designing such antenna systems is presented. As an example, the framework has been used to design an antenna system for deployment at the Thwaites glacier, Antarctica. Design details of six circularly polarized (CP) antennas, one for the englacial sensor probes and five for supraglacial surface receivers are presented. The probe antenna is a 3D bent cross dipole that fits within a borehole of 8 cm diameter while providing a 1 dBic gain at 433 MHz in ice. The other five antennas are printed ones made for use with glacier surface receivers to receive information transmitted by the englacial sensor probes. Out of five, three are cross dipole antennas, while the remaining two are of Archimedean spiral type. All these six antennas provide 3 dB beamwidths of at least 50º in the xz and yz vertical planes catering for transmitter-receiver antenna misalignments caused by extended deployments. The printed cross dipole versions 1 and 2, and the half ring shaped cross dipole antennas for surface receivers provide realized gains of 6.1 dBic, 5.9 dBic, and 5.9 dBic respectively with a quarter wave reflector. The version 2 antenna provides size reduction at the ...