Only when the resonant cavity of microwave Plasma Thruster (MPT) is under the resonant state, the microwave energy can heat propellant gas to produce thrust efficiently.

Rigorous analysis of dielectric-loaded cylindrical resonant cavity is the basis of microwave circuit design and microwave dielectric measurement.

Microwave plasma thruster can generate free-floating plasma brought about by microwave discharge breakdown gas in resonant cavity without the service life problem produced by electrode ablation.