UCLA

For decades, it was believed that the Martian subsurface contains no liquid water but only shallow ground ice. Nevertheless, over the past few years scientists have been discovering on Mars new evidence of liquid water, which is an essential ingredient for life. Post processing high-resolution pictures taken by NASA’s Mars Reconnaissance Orbiter (MRO) revealed sheets of water ice located in the Martian subsurface. To obtain the dielectric spectroscopy of these potential water bodies, a demand has arisen for electrically small loop antennas that can be used on the broadband dielectric spectrometer for future Mars rover missions. The hope among the scientific community is that by sweeping the frequencies of the transmitting electromagnetic waves from 0.8 to 10MHz, the presence of water and hydrated minerals can leave some signature in the reflected wave.

To provide the scientists with the "ears" to listen to the flow of water underneath the Martian surface, proposed in this work are two novel electrically small loop antenna designs for 0.8-10MHz wide-band operation: a single-turn loop antenna with a continuous mechanical frequency tuning capability (Chapter 2) and a reconfigurable multi-turn loop antenna with an electrical frequency tuning capability (Chapter 3). The usage of lumped elements, RF MEMS switch, varactor diodes, transformers, and RF balun in the realm of small antenna designs is investigated. Prototypes have been fabricated, tested and measured (Chapter 4).