Effects of dispersion on electromagnetic parameters of tape-helix Blumlein pulse forming line of accelerator

Zhang, Yun; Liu, J.L.; Feng, Jing

doi:10.1051/epjap/2012110383

Cited by 9 publications

(11 citation statements)

References 23 publications

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“…1. This point is quite different from the infinite long line analyzed in reference [31][32][33]. The traditional nondispersive wave propagation method employs the lumped parameters such as impedances on the two sides of the z i port to calculate the transmission coefficient and reflection coefficient of z i port.…”

Section: Travelling Electromagnetic Waves and Dispersion Relationmentioning

confidence: 92%

“…So, the slow-wave electromagnetic fields of the incident waves in region I (r 1 < r < r 2 ) and region II (r 2 < r < r 3 ) of the ith stage Blumlein line can be calculated in the same forms as shown in formula (A2) and (A3) in reference [31]. In this paper, the formulas for field components aforementioned are not provided.…”

Section: Travelling Electromagnetic Waves and Dispersion Relationmentioning

confidence: 99%

“…2(a) and 2(b) respectively. Reference [31] calculated the harmonic coefficients similar to the parameters shown in (4), and the coefficients represented the proportions of the harmonics in the total field. Through combining (1), (4), (9) and (10), the dispersive transmission matrix and dispersive S-parameter matrix of the electromagnetic waves propagating in multiple stages of helical Blumlein lines are obtained.…”

Section: Analytical Transmission Matrix and S-parameter Matrixmentioning

confidence: 99%

“…The question that how these problems affect the output pulse string should be studied. However, the previous helical dispersion theory based on the approximation of 'infinite long line' in references [31][32][33] can not analyze these wave propagation issues and the relevant physical problems in multiple stages of helical transmission lines with finite lengths.…”

Section: Introductionmentioning

confidence: 99%

“…Through employing the nondispersive travelling wave propagation method based on telegraphers' equation, the transmission and reflection of the square voltage waves at different impedance ports were analyzed in detail in references [28][29][30] without considering the helical dispersion. Through combining the helical dispersion theory and the non-dispersive lumped circuit theory, references [31][32][33] calculated the parameters of tape-helix Blumlein lines, but the employed dispersion theory based on an approximation of "infinite-long line" can not analyze the wave reflection, transmission and the S-parameters at the ports of the helical transmission line with a finite length. In the MHz burst repetitive operations of accelerator and high-power pulse generator, multiple stages of helical transmission lines are used as pulse delay lines and pulse forming lines for output of a pulse string [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Dispersion and Dielectric Effects on Reflection and Transmission of Electromagnetic Waves Propagating in Multiple Stages of Tape-Helix Blumlein Transmission Lines

Liu¹

2013

PIER

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Abstract-Tape-helix transmission lines and helical coils have important applications in communication technology, signal measurement, pulse delay, pulse forming and antenna technology. In this paper, a set of fully dispersive propagation theory based on matrix method is firstly introduced to explain the propagation characteristics of travelling electromagnetic waves in multiple stages of helical Blumlein transmission lines with finite lengths. The different stages of helical transmission lines are filled with different propagation dielectrics, and the effects of dispersion and dielectrics on the propagation matrix and S-parameter matrix of the travelling waves are analyzed in detail. Relations of the exciting current waves in the series-connected helical Blumlein transmission lines are studied, and the dispersive transmission coefficients and reflection coefficients of electromagnetic waves at different dielectric ports are also initially analyzed. As an innovation, the proposed fully dispersive propagation theory which was demonstrated by simulation and experiments can substitute the non-propagating tape-helix dispersion theory and the non-dispersive telegraphers' equation to analyze the helical transmission lines.

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Section: Travelling Electromagnetic Waves and Dispersion Relationmentioning

confidence: 92%

Section: Travelling Electromagnetic Waves and Dispersion Relationmentioning

confidence: 99%

Section: Analytical Transmission Matrix and S-parameter Matrixmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Dispersion and Dielectric Effects on Reflection and Transmission of Electromagnetic Waves Propagating in Multiple Stages of Tape-Helix Blumlein Transmission Lines

Liu¹

2013

PIER

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Impedance matching condition analysis of the multi-filar tape-helix Blumlein PFL with discontinuous dielectrics

Zhang

Liu

2012

Laser Part. Beams

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In this paper, the characteristic impedance matching of the inner line and outer line of the multi-filar tape-helix Blumlein pulse forming line (BPFL) is analyzed in detail by dispersion theory of tape helix. Analysis of the spatial harmonics of multi-filar tape-helix BPFL shows that the integer harmonic numbers of the excited spatial harmonics are not continuous. In addition, the basic harmonic component still dominates the dispersion characteristics of the multi-filar tape-helix BPFL at low frequency band. The impedance mismatching phenomenon caused by the discontinuity of filling dielectrics in the inner line of BPFL is studied as an important issue. Effects of dielectric discontinuity on the coupled electromagnetic fields and the parameters of the outer line are also analyzed. The impedance matching conditions are both obtained under the situations of continuous filling dielectric and discontinuous dielectrics, respectively. Impedance characteristics of these two situations are analyzed by comparison, and effects of the thickness of support dielectric on the impedance are also presented. When the 6 mm-thickness nylon support of the multi-filar tape helix is used in the filling dielectric of de-ionized water, the characteristic impedances of the inner line and outer line of BPFL are 53 Ω and 14.7 Ω, respectively. After the improvement about substituting de-ionized water by castor oil, the relative permittivities of the support dielectric and filling dielectric are almost the same, and the impedances of the inner and outer line of BPFL become 80 Ω and 79 Ω, respectively. That is to say, the impedance mismatching problem caused by dielectric discontinuity is solved. Circuit simulation and experimental results basically correspond to the theoretical results, and the fact demonstrates that impedance analysis of the multi-filar tape-helix BPFL based on dispersion theory is correct.

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Dispersion analysis of the solid helical pulse-forming line

Wang

Liu

2015

Laser Part. Beams

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In this paper, a solid helical pulse-forming line (HPFL) is described. The electromagnetic (EM) dispersion theory is used to calculate the important parameters of the HPFL based on tape helix model. Dispersion effects on the important EM parameters of HPFL, such as electric length and characteristic impedances, are analyzed. When Al2O3 ceramic is applied to be the dielectric in the HPFL, the pulse width of the HPFL is calculated nearly 50 ns only with the length of 305 mm. EM field simulation can draw the dispersion curve of the HPFL directly, which can describe the dispersion effect on the electric length of HPFL. Furthermore, the EM field simulation and experiments are carried out to verify the theoretical calculations of the pulse wide and characteristic impedances. Both simulation and experimental results can prove the EM analyses and calculations in this paper.

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Effects of dispersion on electromagnetic parameters of tape-helix Blumlein pulse forming line of accelerator

Cited by 9 publications

References 23 publications

Dispersion and Dielectric Effects on Reflection and Transmission of Electromagnetic Waves Propagating in Multiple Stages of Tape-Helix Blumlein Transmission Lines

Dispersion and Dielectric Effects on Reflection and Transmission of Electromagnetic Waves Propagating in Multiple Stages of Tape-Helix Blumlein Transmission Lines

Impedance matching condition analysis of the multi-filar tape-helix Blumlein PFL with discontinuous dielectrics

Dispersion analysis of the solid helical pulse-forming line

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