title: Waveguide transition with vacuum window for multiband dynamic nuclear polarization systems.
abstract: A low loss waveguide transition section and oversized microwave vacuum window covering several frequency bands (94 GHz, 140 GHz, 188 GHz) is presented. The transition is compact and was optimized for multiband Dynamic Nuclear Polarization (DNP) systems in a full-wave simulator. The window is more broadband than commercially available windows, which are usually optimized for single band operation. It is demonstrated that high-density polyethylene with urethane adhesive can be used as a low loss microwave vacuum window in multiband DNP systems. The overall assembly performance and dimensions are found using full-wave simulations. The practical aspects of the window implementation in the waveguide are discussed. To verify the design and simulation results, the window is tested experimentally at the three frequencies of interest.
authors.affiliation: Technical University of Denmark, Ørsteds Plads 349, 2800 Kgs. Lyngby, Denmark.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Rybalko
authors.affiliation: Technical University of Denmark, Ørsteds Plads 349, 2800 Kgs. Lyngby, Denmark.
authors.forename: Sean
authors.initials: S
authors.lastname: Bowen
authors.affiliation: Technical University of Denmark, Ørsteds Plads 349, 2800 Kgs. Lyngby, Denmark.
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Zhurbenko
authors.affiliation: Technical University of Denmark, Ørsteds Plads 349, 2800 Kgs. Lyngby, Denmark.
authors.forename: Jan Henrik
authors.initials: JH
authors.lastname: Ardenkjær-Larsen