In a micro gas turbine engine, a capacitive sensor is used for measuring a tip clearance of a radial compressor section thereof, and an actuator is used for axially displacing a rotor shaft in response to an output from the capacitive sensor. The bracket includes two sidewalls. According to further aspects of the invention, delivery systems for a fatigue resistant stent and methods of use are provided. The circuit arrangement has a high capacitance per unit area and can be fabricated in a simple way.