A twystron is a type of

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...

-producing

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...

most commonly found in high-power

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

systems. The name refers to its construction, which combines a

traveling wave tube A traveling-wave tube (TWT, pronounced "twit") or traveling-wave tube amplifier (TWTA, pronounced "tweeta") is a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range. The TWT belongs t ...

, or TWT, with a

klystron A klystron is a specialized linear-beam vacuum tube, invented in 1937 by American electrical engineers Russell and Sigurd Varian,Pond, Norman H. "The Tube Guys". Russ Cochran, 2008 p.31-40 which is used as an amplifier for high radio frequenci ...

, producing a tw-ystron. The name was originally a trademark of

Varian Associates Varian Associates was one of the first high-tech companies in Silicon Valley. It was founded in 1948 by Russell H. and Sigurd F. Varian, William Webster Hansen, and Edward Ginzton to sell the klystron, the first vacuum tube which could amplify ...

, its developer, and was often capitalized. In recent times has become a generic term for any similar design. The twystron amplifies a source signal using a conventional klystron, which consists of a series of cylindrical resonant chambers fed with the source signal. An

electron gun An electron gun (also called electron emitter) is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy. The largest use is in cathode-ray tubes (CRTs), used in nearly ...

at one end of the tube produces

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...

s that flow through a holes in the centers of the resonators. As they pass through the holes, the signal within the resonator causes the electrons to "bunch up", a process known as velocity-modulation. The resulting electron beam is an amplified version of the original signal. In a conventional klystron, this signal is then captured and used as the output. In the twystron, the output instead flows into a TWT for further amplification. The advantage of this approach is that while the multi-resonator klystron is an efficient amplifier, its

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

is reduced as one adds additional resonators, which makes high-power klystrons have a relatively low bandwidth generally less than 10% of the design frequency. In contrast, the TWT has a wider bandwidth response but are generally very long. By combining a klystron with a TWT, the result is a relatively compact device with improved bandwidth; typical twystrons have bandwidth up to 15% of the design point. The device was developed by Albert La Rue and Rodney Rubert in the early 1960s and was quickly adopted by many radar designs in order to improve

frequency agility Frequency agility is the ability of a radar system to quickly shift its operating frequency to account for atmospheric effects, jamming, mutual interference with friendly sources, or to make it more difficult to locate the radar broadcaster through ...

and thereby improve performance against radar jamming systems. The twystron was generally replaced by the

extended interaction klystron Extension, extend or extended may refer to: Mathematics Logic or set theory * Axiom of extensionality * Extensible cardinal * Extension (model theory) * Extension (predicate logic), the set of tuples of values that satisfy the predicate * E ...

and solid state amplifiers.

References

* * {{cite conference , url=https://ieeexplore.ieee.org/document/1473841 , title=Multi-megawatt hybrid TWT's at S-band and C-band , first1=Albert , last1=La Rue , first2=Rodney , last2=Rubert , conference=1964 International Electron Devices Meeting , date=31 October 1964 , doi=10.1109/IEDM.1964.187444 Radar theory Vacuum tubes Microwave technology