coupled-cavity traveling-wave tube

electronics

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June 24, 2026

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A coupled-cavity traveling-wave tube (TWT) is a type of electron tube used for amplifying microwave signals over broad bandwidths. It operates by interacting a beam of electrons with an electromagnetic wave.12

The key components of a TWT include an electron gun, a focusing structure, an RF circuit, and a collector. In a coupled-cavity TWT, the RF circuit consists of a series of staggered cavities linked together for wave propagation. This design limits the bandwidth to typically 10 to 20 percent.1

The interaction between the electron beam and the RF wave causes the wave to grow, resulting in amplification. TWTs are known for their high efficiency, often between 50 to 75 percent, and are used in applications like communications satellites due to their reliability and low RF distortion.1

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electron tube
Traveling-wave tubes
…cavities have bandwidth limitations, the coupled-cavity TWT also is bandwidth-limited to typically 10 to 20 percent. The helix TWT, however, has no particular bandwidth limitations, and, for all practical purposes, an octave bandwidth (100 percent) is attainable.
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…cavities have bandwidth limitations, the coupled-cavity TWT also is bandwidth-limited to typically 10 to 20 percent. The helix TWT, however, has no particular bandwidth limitations, and, for all practical purposes, an octave bandwidth (100 percent) is attainable.
Read More