A 500-W coupled-cavity TWT for Ka-band communication

Commun. & Power Industries, Palo Alto, CA, USA
IEEE Transactions on Electron Devices (Impact Factor: 2.47). 06/2005; 52(5):665 - 668. DOI: 10.1109/TED.2005.845867
Source: IEEE Xplore


Worldwide demand for high-power amplifiers for digital satellite communication at Ka-band frequencies between 27 and 31 GHz is steadily increasing (2003). Communication and Power Industries (CPI) has developed a 500-W periodic permanent magnet focused coupled-cavity traveling wave tube (TWT) for conduction-cooled amplifier systems, which is being introduced into the commercial satellite communication market. The TWT is capable of greater than 500-MHz instantaneous bandwidth and is cathode voltage tunable from 28.3 to 30 GHz. The TWT may be operated saturated at the 500-W output power level or backed off from saturation in the linear mode. CPI's Satcom Division has integrated the TWT into a conduction-cooled transmitter box suitable for antenna hub-mount applications. The amplifier uses predistortion networks to provide a high degree of linear response when operated in output power back-off mode.

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    • "However, it has to face to the size and power limitation at this frequency range, when using traditional helical traveling wave tube [1] [4] and some novel structure TWTs [5] [6] [7] on such high-frequency band. However, some metal structure TWTs (Coupled Cavity (CC) TWT [8], FWG TWT [9] [10], and so on) can obtain high power but low gains in single tube for strong backward wave oscillation (BWO) instability, also for some FWG cascaded TWTs [11] [12] and CC-FWG cascaded TWTs [13]. "
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    ABSTRACT: A design of a V-band Helix-Folded Waveguide (H-FWG) cascaded traveling wave tube (TWT) is presented. In this cascaded structure, a digitized nonlinear theory model is put forward first to simulate these two types of the tubes by common process. Then, an initial design principle is proposed, which can design these two different kinds of tubes universally. Using this principle, a high-gain helix TWT is carefully designed as a first stage amplifier followed by a FWG TWT to obtain high power. Simulations predict that a peak power of 800 W with saturated gain of 60 dB from 55 GHz to 60 GHz can be achieved.
    Full-text · Article · Jun 2015 · Active and Passive Electronic Components
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    • "In this paper, we present the design and simulation of a Ka-band double-slot staggered CCTWT based on CPI's CCTWT [4] by using the 3-D PIC code MAGIC3D in order to investigate and understand the beam dynamics in the CCTWT. We simulated the Ka-band CCTWT in [4] by using similar parameters such as beam voltage, beam current, and slowwave structure dispersion characteristics. MAGIC3D is a 3-D, fully dynamic, and self-consistent PIC code used to simulate plasma-physics problems [15]. "
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    ABSTRACT: The 3-D particle-in-cell (PIC) simulations of a Ka-band coupled-cavity traveling-wave tube (CCTWT) are shown. The computational analysis of the Ka-band coupled-cavity slow-wave structure was conducted through the use of an electromagnetic PIC code MAGIC3D. The choice of a double-slot staggered RF cavity circuit was made because of a wide frequency bandwidth, moderate interaction impedance, and excellent thermal dissipation properties. We investigated the large-signal and nonlinear beam dynamics of a Ka-band CCTWT using MAGIC3D. The center frequency of the Ka-band CCTWT can be tuned from 28.4 to 30 GHz by varying the cathode voltage. Hot-test simulations show that the 84-cavity Ka-band CCTWT produces 540 W of saturated output power at 29 GHz with an electronic efficiency of 8.1% and a gain of 28 dB when the beam voltage and current are set to 17 kV and 390 mA, respectively.
    Preview · Article · Feb 2009 · IEEE Transactions on Electron Devices
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    ABSTRACT: Boeing EDD continues to make advances in its millimeter-wave helix-TWTs by pushing the CW output power capability and increasing the overall efficiency of Ka-band and Q-band devices for communications. The 8921HP, EDD's latest high power Ka-band TWT model, demonstrates 250 W to 300 W CW output power and 47 % minimum overall efficiency with a two-stage collector over 27.5 GHz-31 GHz. In Q-band, the 8925HP, derived from the current production 120 W Q-Band helix-TWT (8905HP), significantly extends the CW output power capability demonstrating 230 W minimum over 43.5 GHz-45.5 GHz. The beam focusing is improved in both the Ka-band and the Q-band TWT models, with RF beam interception well below 1% of the nominal beam current of 95 mA. The above devices are primarily designed for CW operation but can also be operated in pulsed mode by using the focus electrode to cut-off the beam. The electron gun typically requires a focus electrode voltage of -800 V with respect to the cathode for beam cut-off.
    No preview · Conference Paper · May 2004
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