There are many applications in which it would be useful to combine the outputs of power sources to provide a higher combined output.
Magnetrons are one of the most efficient generators of high power RF in terms of their size and electronic efficiency. Unfortunately at higher RF power levels the magnetron design inherently starts to become less efficient, although the efficiency is still superior to many other types of device. One potential solution to achieve higher power levels is to combine the outputs of several magnetrons.
Where the power sources are magnetrons, it is generally desirable to use a technique that enables phase and frequency locking of the magnetron outputs so that they are in phase as this maximises the available combined output power. There are a number of different approaches that may be used to implement phase and frequency locking, for example, by signal injection from a seeding magnetron, by phase and frequency locking through power supply modulation or by power combining techniques. Power combining for arrangements using magnetrons may employ circulator technology which tends to be reliable but very expensive. Another approach uses hybrid technology but while this is cheaper it is not very effective in obtaining high power outputs.