Non-resonant metamaterials for high power vacuum electronics applications

Summary form only given. Recent years have seen a growing interest in the development of novel electromagnetic media, such as metamaterials. Unlike conventional materials, metamaterials derive their properties from their structure rather than their composition. These artificial, periodic, materials can be engineered to give a specific response to an electromagnetic wave and mediate novel particle wave interactions. Current realizations of metamaterials consist of periodic arrays of resonant sub-structures, where the use of resonant substructures results in high-losses and narrow bandwidth operation. This means these materials are less than desirable for high-power vacuum electronic devices, as the material structure cannot withstand high-power microwave interactions. In the work presented here we consider a metamaterial constructed from non-resonant unit-cells with a near zero effective permittivity and permeability. This results in a low loss, broadband, material that can mediate novel particle-wave interactions. This low-loss enables the material to operate in the presence of high-power microwaves without destruction. We discuss the advantages and disadvantages these materials can offer, and the interaction and energy transfer between wave and beam. We discuss the use of these materials in high power vacuum electronics, and how these materials can offer novel microwave generation and amplification technologies.