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Journals and Conferences
Recent research and development has been incredibly successful at advancing the capabilities for vacuum electronic device (VED) sources of powerful terahertz (THz) and near-THz coherent radiation, both CW or average and pulsed. Currently, the VED source portfolio covers over 12 orders of magnitude in power (mW-to-GW) and two orders of magnitude in frequency… (More)
The design, fabrication, and electromagnetic cold testing results of an all-copper grating circuit intended for a G-band sheet-beam traveling-wave amplifier are presented. Fabrication was carried out via ultraviolet photolithography (UV-LIGA) using the SU-8 photoresists. Two cold test methods used to characterize the microfabricated circuits are reported… (More)
Recently, dynamic nuclear polarization enhanced nuclear magnetic resonance (DNP/NMR) has emerged as a powerful technique to obtain significant enhancements in spin spectra from biological samples. For DNP in modern NMR systems, a high power continuous-wave source in the submillimeter wavelength range is necessary. Gyrotrons can deliver tens of watts of CW… (More)
Wideband, distributed beam amplifiers are under development at NRL. We report on microfabrication techniques used to construct several types of millimeter wave planar amplifier circuits using Ultraviolet Lithography (UV-LIGA).
A wideband 220 GHz vacuum electronic amplifier is under development utilizing a novel method to fabricate 3D structures comprised of polymer monofilaments to form the beam tunnels and SU-8 to form the electromagnetic circuits. The complete structures are simultaneously formed in one UV-LIGA step. The method shows promise for THz VE microfabrication.
The general electromagnetic properties and design methodology for serpentine/folded-waveguide (FW) amplifiers are presented. In addition, hybrid-waveguide circuit topologies, which permit greater design flexibility than the basic serpentine/FW topologies, are also introduced, and their dispersion characteristics are discussed. Experimental validation of… (More)
We present electromagnetic cold-test measurements of BeO ceramic pillbox vacuum windows for a 220-GHz traveling-wave tube amplifier. Transmission and reflection measurements show better than 20 dB return loss over a 25 GHz bandwidth, with band centers in the range of 212-225 GHz. We observe tuning of the window response as the circular waveguide length is… (More)
A 50 watt CW 220 GHz sheet beam amplifier is under development at NRL. We report on microfabrication techniques used to construct a grating-based amplifier circuit using Ultraviolet Lithography (UV-LIGA) and Deep Reactive Ion etching (DRIE).
The theory, design and experimental results of a wideband 140 GHz, 1 kW pulsed gyro-traveling wave amplifier are presented. The gyro-TWA operates in the HE(0,6) mode of a novel cylindrical confocal waveguide using a gyrating electron beam. The electromagnetic theory, interaction theory, design processes and experimental procedures have been described in… (More)
Designs and simulated performance for W-band traveling wave tubes are presented for three slow wave structure types (dielectric, serpentine waveguide, and cavity-loaded helix). Output powers are 120 and 245 W at 94 GHz for dielectric and serpentine, respectively, with 5-6 GHz bandwidth (9 GHz in serpentine with equalization).