This invention relates to a method and apparatus for amplifying radio-frequency (rf) energy for injecting into an adjacent load, and more particularly, to a method and apparatus for coherent rf injection with a plurality of amplifier tubes. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).
It is frequently necessary to use a plurality of amplifiers which operate in parallel to deliver an output signal with the desired strength to a resonant cavity. In such cases the parallel amplifiers might be located remote from the resonant cavity, where the output from the amplifiers is combined for transmission to the resonant cavity. In other instances, amplifier assemblies are mounted in parallel on the resonant cavity for directly injecting the amplified signals within the cavity.
Where the amplifiers are remotely located, it will be appreciated that the delivered power can be affected by transmission losses. It will also be noted that the transmission line characteristics can change with age and with ambient conditions with resulting changes in line impedance, signal phase change, resonant frequencies, etc. For direct mounting of amplifiers about a resonant cavity, independent coaxial input cavities are conventionally used with amplifier tubes and must be individually mounted and driven about the load. A substantial amount of ancillary equipment is required to monitor and to maintain the amplifier outputs in coherent phase relationships.
Accordingly, it is an objective of the present invention to directly couple rf input and output to a resonant load.
It is another object of the present invention to minimize ancillary equipment in maintaining coherent phase relationships between parallel amplifiers.
One other object of the present invention is to simplify the installation of a plurality of amplifier tubes about a resonant load.
Another object of the present invention is to maintain input-output impedance matching over a wide range of circuit conditions.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.