STTR Phase I: Metamaterial Based Vacuum Electron Devices for Next Generation Communication Systems

This Small Business Technology Transfer (STTR) Phase I project aims to develop novel technology for Vacuum Electron Devices (VED) such as Traveling Wave Tubes (TWT) for the next generation high spectral efficiency, high data rate civilian and military communication systems. VED amplifier performance be greatly improved by employing frequency selective interaction structures (IS) with high gain in the operating band and negligible spurious output in the neighboring bands for achieving high spectral efficiency. This project aims to develop a novel TWT with a metamaterial (MTM) IS. MTMs can be engineered to simultaneously have large negative values of permittivity (å) and permeability (ì) which cause left handed propagation of electromagnetic waves with high coupling to the electron beam. Also, such structures allow co-propagation of an electron beam in the medium of the IS, permitting the choice of a spatially distributed high current electron beam to achieve higher gain and output power. As a result of the proposed research an MTM IS for a 10 GHz TWT will be designed, tested and characterized. A proof-of-concept TWT design will be developed which will have potential to advance the state-of-the-art in high data rate communication systems. The broaderimpact/commercial potential of this project includes advances in novel designs of passive components such as waveguides, filters, duplexers, power combiners and channel drop filters. Advances in the performance of these components are crucial to advancing system-level performance of the next generation communication systems. The design methodology developed under this work will also be applicable to other microwave and terahertz sources such as VED based gyrotrons and semiconductor based Terahertz sources such as Quantum Cascade Lasers (QCL) by using an MTM structure to improve confinement ofdesired modes and filtering the unwanted modes. Also, further development of MTMs will create new technology for the manipulation and transportation of light which is the basic building block for optical computing. The development of the concept of using MTMs for solving problems in both active andpassive microwave and terahertz devices will contribute to the understanding of the basic physics of MTMs and advance the field of microwave engineering.