Analysis of a new crossed-field amplifier, the "EAL," or electromagnetic amplifying lens

A new form of crossed-field microwave and millimeter wave amplifier which combines an interaction process that results in axial gain with a quasi-optical handling of the RF input and output power is described. Because of its functional similarity to a microwave lens and the additional property of amplification, it is called the Electromagnetic Amplifying Lens. Its advantages are outlined, and its interaction mechanism considered in detail. It is shown that the voltage gain is a linear function of distance in the useful operating range. When the RF level is low, interference between forward- and backward-traveling waves on the waveguide results in loss of control of the space charge. This phenomenon limits the gain available with stable device operation; useful gain of at least 20 db is theoretically possible with a bandwidth of several per cent. The crossed-field interaction principle that is employed assures efficiencies of better than 50 per cent.