High power compact microwave source

#This invention relates to microwave generators and specifically to high-power microwave generators.

#Conventional microwave generation units have ranged from small low-power units such as in microwave ovens to very large high-power units such as in large test labs, each with microwaves generated by electron beam excitation of a microwave generation tube. All existing high-power microwave units (above 100 MW power) use field emission to produce the electron beams, requiring fields of typically 1/3 to 1 MV. Conventional units capable of sufficient power (over 100 MW) to burn out or upset electronic military systems have typically taken up at least about 200 cubic feet (more typically 2000 cubic feet) and weighed in excess of a ton (more typically 0.10 tons) due to the need for a vacuum region and (usually) a magnetic field to guide the beam as well as the magnetic field to create the emission and require power sources of up to 10 GW capacity, thus making them impractical for most military operations. There is a military interest in reducing the size and power requirements of high-power microwave units for military applications to allow them to be mounted on vehicles, small boats and planes, and missiles. A fresh approach to microwave generation is needed to achieve such size reductions.

#The present invention gives this fresh approach to the above need by providing a compact high-power microwave generator using very high speed switching of an electrically charged resonator circuit to achieve a direct conversion from pulsed power to microwaves with no intervening medium.

#The invention will be better understood by reference to the attached drawings in which:

#FIG. 1 is a schematic diagram of a conventional prior-art microwave generator.

#FIG. 2 is a schematic diagram of a microwave generator of the present invention.

#Referring now to FIG. 1, a conventional microwave generator (10) is shown comprising typically a prime power supply (12), a power conditioning unit (14), an electron beam source (16), a vacuum pump system (18), a magnetic field source (20), a microwave tube (22), and an antenna (24). The prime power supply (12) provides the electrical current to drive the generator (10) and supplies this current to a power conditioner which converts the energy supplied by the power supply into the proper form for powering the electron beam source (16), which supplies electron beams to a microwave generation tube (22), which is in turn coupled to an antenna (24) to direct the generated microwaves. Such a unit is conventional in the pulsed power field. Typical of such units are the "Camel" and "Camel-X" facilities of Physics International Company at San Leanalto, Calif.

#The conventional electron beam source supplies electron beams by field emission techniques, which require a vacuum and a strong magnetic field, both of which, in turn, require sizable pieces of equipment and introduce inefficiencies into the system. Referring to FIG. 2, the present invention eliminates the electron beam source and instead provides a microwave generation unit which comprises a prime power source (26), a power conditioner (28), a compact microwave source (30), and an antenna (32). It is with the microwave source (30) that the present invention is primarily concerned.

#Referring to FIGS. 3 and 4, the source (30) is a transmission line cavity resonator (34) having the capacity to hold a charge of greater than 100 kV with an output switch (36) therein. The output switch (36) can be any device which will withstand high voltage and close quickly (subnanosecond) when required to do so, and which has very low circuit inductance (37) and a very low closed resistance (38).