Microwave Beaming Propulsion (MBP) is a kind of Beamed Energy Propulsion(BEP).
BEP is the system which gains propulsive energy by high power beamed electromagnetic wave transmitted from outside of the thruster.
Because BEP vehicles do not need to load an energy source, such as fuel tank and pump system, heavy electric source, or atomic reactor, the BEP propulsion thruster is very simple. And more, atmospheric air can be utilized as propellant through the flight in the atmosphere, the vehicle can achieve remarkably high payload ratio. As the propulsive energy is provided from the ground, the ground based beam station can be used for launch again and again.
Therefore BEP technology is expected to realize extremely low-cost to-orbit-launch system.

Microwave-beaming has some advantages in comparison with laser-beaming:
1) The development cost of microwave generators is generally two-orders lower than that of laser oscillators.
2) A single beam at the power level of GW will be obtained by clustering microwave generators with the use of phased array technology.

The research on launch cost by MBP system shown that cost becomes almost one-tenth of chemical rocket's cost with 1,000 launches by MBP.