Colin D. Joye

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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)
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)
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).