High-power Traveling Wave Tube Amplifiers Research Articles

Curved Ring-Bar Slow-Wave Structure for Wideband MW-Power Traveling Wave Tubes

A coupled transmission line (TL)-based slow-wave structure is presented and characterized. This TL is a modified ring-loop structure referred to as curved ring bar. It inherits the features of the ring-loop structure, but includes elliptic loops to enhance the axial electric field for TM01 mode. The structure demonstrates wideband behavior and is especially designed for high-power traveling wave tube amplifiers. It is characterized using a pair of uniform and identical coupled TLs utilized to achieve desired dispersion characteristics. This characterization explains the dispersion curves and interaction impedance. A simple way to derive dispersion behavior in terms of circuit parameters is also provided. A traveling wave tube (TWT) model is also presented that gives an output power of 1 MW across 1.8–2.4 GHz. It is noted that the designed TWT provides a bandwidth of 20% and delivers an output power of 1 MW, larger than previously reported in S-band.

Key telecommunications technologies for increasing data return for future Mars exploration

NASA's plans for Mars exploration demand increasing telecommunications capabilities in the coming decades. Ambitious robotic missions will deploy high-rate instruments in Mars orbit and on the Martian surface, with increasing spatial, spectral, and temporal resolution. Orbiters will require high-performance direct-to-Earth links, while landed missions will benefit from energy-efficient communications through relay-equipped orbiters to increase data return while minimizing landed mass. The Mars Reconnaissance Orbiter and the Mars Exploration Rovers define the current state-of-the-art for Martian orbiters and landers, respectively. Even with respect to these capabilities, however, significant growth appears to be very feasible based on infusion of relatively mature technologies. Deployable spacecraft antennas, high-power traveling wave tube amplifiers, and migration to Ka-band provide a path to much higher spacecraft equivalent isotropic radiated power. When combined with proposed upgrades to the Deep Space Network, future orbiters can envision downlink rates more than two orders of magnitude beyond current capability. Similar growth can be achieved on relay links between landers and relay orbiters, based on improved relay capabilities which can be infused into the current generation of Electra software-defined relay radios, and by migration to high-frequency directional relay links.

An experimental long-slot coupled circuit high-power traveling-wave tube amplifier

Cylindrical cavities coupled together by long circumferential slots in their common walls have been shown to be a suitable circuit for wideband high-power traveling wave tube amplifier. A single sever tube has been designed for the following characteristics: Beam Voltage 100 kv Beam Current 60 amp Small Signal Gain 30 db Small Signal Bandwidth \sim 18% Peak Power > 1.5 Mw Details of the construction and the characteristics of the various components will be given. The slot staggering introduced to break up the slot resonance pass-band (backward) has been completely effective and shows the adequacy of this technique for future work.