A study of various beacon antennas for an orbiting sample container of a future mars sample return mission

This paper presents some results of a study of various options for a near-omnidirectional low-gain antenna at UHF frequencies, for a Mars Orbiting Sample Return Container (OS). The OS is part of a concept study for a future mission to return samples from Mars. It is a critical component of such a mission which contains the Mars samples. It would be returned by a separate spacecraft to Earth. The OS will be identified and located by the spacecraft for pick-up from orbit by a beacon signal broadcast via a surface antenna. Several antenna designs were considered, but two promising ones are presented here which have good patterns with a better than 2:1 VSWR (Voltage Standing Wave Ratio), but meet different criteria for OS design. One is a patch type antenna and the other a slot type antenna. Some data and test results of a fabricated breadboard antenna as well as discussions are provided.