Patent ID: 8330345

Claim:
An active electronically steered cathode (AESC) comprising: a cathode having an emissive surface; a control grid situated in close proximity to the cathode and defining a G-K gap between the cathode and the control grid, wherein the control grid is biased to maintain a voltage potential with respect to the cathode; an enclosure substantially enclosing the cathode and the G-K gap and having a first input port adapted to couple a first radio-frequency (RF) signal into the G-K gap, and a second input port adapted to couple a second RF signal into the G-K gap, wherein: the first RF signal and the second RF signal combine to produce an electromagnetic field in the G-K gap having at least one electromagnetic field maximum near a portion of the emissive surface of the cathode such that the at least one electromagnetic field maximum and the voltage potential of the control grid define at least one emission site on the cathode and cause the cathode to emit an electron beam from the at least one emission site.