The Design and Development of a 30-GHz Microwave Electrothermal Thruster

We report initial results on the design and development of a 30-GHz MET suitable for use as a propulsion system on a CubeSat platform. Electromagnetic modeling was used in the design of the 30-GHz thruster to determine the optimal input antenna size and length. A 2.4-mm antenna size was chosen with a length that is flush with the bottom of the cavity. Modeling also shows how accuracy in machining of the cavity radius affects thruster performance. The modeling results indicate that radius inaccuracies on the order of ±0.1 mm result in mode distortion, shifting of the resonant frequency, lowered electric field strength, and poor power transfer to the cavity. The expected power requirement for plasma ignition is 5-10 watts. Initial testing is being performed at a pressure of 30 Torr using helium as the propellant