Self-winding Helices as Slow-wave Structures for mm and sub-mm Travelling Wave Tubes
Abstract
In the three years of the project, we made significant progress in predictive modeling, synthesis, and characterization of self-assembled SWSs for millimeter-through THz vacuum electronic de-vices. This progress was made despite COVID-19 severely hampering our work by forcing laboratories to be closed for 5 months and under limited operations for 10 additional months over the duration of the award. Our accomplishments include a rapid assessment of the performance of cold and hot helices as their parameters vary in a practically realizable space by self-assembly of NMs. These parameters include diameter to pitch ratio, tape width (i.e., width of the NM strips or ribbons), surface rough-ness, substrate type, and the geometry of the enclosing waveguide of the helix. 3D simulation models and understanding of beam-wave interaction in self-assembled helices with single and double chirality; predictive models of the relaxation pathway of conductive ribbons into self-assembled helices; robust and mass-producible helices with high thermal conductance and electrical conductance and a novel approach to their fabrication based on self-assembly of conductive ribbons during electroplating; a scalable device design that integrates a helical SWS and two coaxial horn antennas to couple radiation in and out of the helix; devices for on-wafer characterization of cold helices; a customized set-up for the characterization of cold helices up to 650 GHz; characterization of cold helices between 60 and 90 GHz; optimal designs for heat management; several refereed publications, patents, and invited and contributed talks at international conferences; training of students and post-docs via a cross-disciplinary and multi-institution mentoring program.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 13, 2022
- Accession Number
- AD1230689
Entities
People
- Daniel W. Van Der Weide
- Francesca Cavallo
- Max G. Lagally
Organizations
- University of New Mexico
- University of Wisconsin–Madison