This is the stuff of UFO’s. No exhaust trail etc.
Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum
It was previously reported that radio-frequency (RF) resonant cavities generated anomalous thrust on a low-thrust torsion pendulum [1,2] in spite of the apparent lack of a propellant or other medium with which to exchange momentum. It is shown here that a dielectrically loaded, tapered RF test article excited in the transverse magnetic 212 (TM212) mode (see Fig. 1) at 1937 MHz is capable of consistently generating force at a thrust-to-power level of 1.2±0.1 mN/kW
China has a usable prototype?