Miniaturized electric propulsion in Low Temperature Co-fired Ceramic

Abstract

Miniaturized propulsion systems are of particular interest in the development of the newer generation of nano-satellites. These small satellites require a low-thrust propulsion system that is highly efficient in the use of propellant. Currently an electric propulsion device is being developed using the unique capabilities of Low Temperature Co-fired Ceramic (LTCC) materials to fit this purpose. In addition to being a stable, vacuum compatible material with high temperature capability, LTCC is a high permittivity material, with e r =7.8 and a loss tangent of 0.0061. The antenna design implements an Inductively Coupled Plasma (ICP) source2 using a spiral antenna embedded in the LTCC. The antenna's spiral is fabricated in silver paste using a direct-write tool, and is in total 11cm long and 1cm in diameter. It is being analyzed for effectiveness in the range of 450MHz–1GHz; the high permittivity causes the length of the antenna's spiral to be approximately one electrical wavelength long with respect to the operating frequency. This gives the antenna interesting characteristics within the 450MHz–1GHz range due to interference patterns generated by the relatively large length of the conductor and its spiraling pattern. As part of this project an analysis of the antenna characteristics and plasma coupling is being done using the COMSOL Multiphysics modeling software3 along with COMSOL's RF and Plasma Modules. The simulation results will be compared with the experimental results for the antenna and thruster assembly including antenna electric field patterns, plasma start power versus frequency and pressure, and plasma density measurements.