Self winding Helices as Slow wave Structures for mm and sub mm Travelling Wave Tubes
Abstract
We address the grand challenge of reliable fabrication and predictive control of helical slow wave structures (SWSs) for millimeter wave through terahertz (THz) traveling wave tubes (TWTs). Our transformative path to miniaturization of SWSs relies on replacing the wire helix that is the central feature of a TWT with a helix formed by self winding nanomembranes (NMs) such as Si-SiGe and Graphene-Ge bilayers. We will thus be able to make micro and nanoscale diameter structures whose dimensions can be precisely controlled in that they depend on residual strain in an epitaxial or non epitaxial NM, the stiffness of the NM, and the geometry of the NM in the plane perpendicular to its thickness. This research program is a comprehensive effort to validate our hypothesis through a highly synergistic theoretical, computational, and experimental approach. Modeling will yield an accurate predictive evaluation of proposed designs prior to experimental prototyping and testing. Our proposed characterization effort will encompass detailed investigation of the structure of the helices, measurements of DC and AC conductivity of the fabricated helices, and tests of cold (without electron beam) and hot (with electron beam) SWSs. The anticipated outcomes of this research are: 1) a robust approach to design, fabricate, test, and optimize SWSs based on self winding NMs; 2) SWSs that can be precisely scaled for operation at millimeter through THz frequencies; 3) amplification of millimeter and sub millimeter waves by the fabricated SWSs.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910086
Entities
People
- Francesca Cavallo
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of New Mexico