Active Antenna Design for Lunar-Based Detection of Global 21cm-Signals from the Dark Ages

This paper concerns the parameters, simulations and techniques involved in designing an active antenna system for detection of global 21cm-signals originating from the Dark Ages at the Lunar far side. A 10.5 m diameter equiangular spiral plate antenna is fashioned to operate from 10 to 70 MHz whilst maintaining a virtually frequency-independent impedance characteristic and radiation pattern. Combined with the stable and low noise performance of the measured PHA-13LN+ amplifier evaluation board, the simulations show that the full active antenna system is well suited to the science objective of this paper.