Wave propagation characteristics in anisotropically conducting dielectric loaded tape helix slow wave structures
22 Apr 2014-pp 327-328
TL;DR: In this paper, the dispersion equation for the infinitesimally thin and anisotropic conducting tape is derived from an exact solution of a homogeneous boundary value problem for Maxwell's equation.
Abstract: The practically important case of dielectric loaded tape helix enclosed in a perfectly conducting coaxial conductor is analysed in this paper. The dispersion equation for the infinitesimally thin and anisotropically conducting tape is derived from an exact solution of a homogeneous boundary value problem for Maxwell's equation. The boundary value problem is solved to yield the dispersion equation which takes the form of the solvability condition viz., the determinant of the infinite-order coefficient matrix is zero. For the numerical computation of the approximate dispersion characteristics, all the entries of the symmetrically truncated version of the coefficient matrix are estimated by summing an adequate number of the rapidly converging series for them. The numerical computation of dispersion characteristics and phase speed variations for different values of b/a (outer conductor to inner helix radius) and effective dielectric permittivity is presented.
Citations
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TL;DR: In this paper, the large-signal behavior of traveling wave tube amplifier for a linear beam dielectric loaded anisotropic conducting tape helix slow wave structure (SWS) was realized through a swift and reliab...
Abstract: The large-signal behavior of traveling wave tube amplifier for a linear beam dielectric loaded anisotropically conducting tape helix slow wave structure (SWS) is realized through a swift and reliab...
13 citations
Cites background or methods from "Wave propagation characteristics in..."
...The normalized propagation phase constants βm(m > 0) in (23) are obtained from the cold wave analysis of the anisotropically conducting tape helix SWS supported by dielectric support rods [4,26] at the radian frequenciesmω0....
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...(ii) Anisotropically conducting tape helix supported by rectangular cross-sectional dielectric rods is considered for the SWS [4,26]....
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...The dispersion relation of the anisotropically conducting tape helix SWS obtained from [4,26] is solved for the chosen dimensions of the SWS given in Table 2....
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01 Sep 2016
TL;DR: In this article, the dispersion equation of a dielectric loaded tape helix slow wave structure surrounded by a conductor or a conductor placed inside the helix is derived from accurate boundary conditions.
Abstract: The tape helix slow wave structures used in travelling wave tube (TWT) amplifiers are exploited for use as radiating devices through the fast wave analysis. The dispersion equation is derived from accurate boundary conditions that neither involve assumptions on the current density distribution, nor considers a defined distribution function for a dielectric loaded tape helix slow wave structure surrounded by a conductor or a conductor placed inside the tape helix. Analytical computation of the dispersion characteristics of both the structures revealed the presence of fast wave modes usable for applications such as antennas.
1 citations
25 Apr 2023
TL;DR: In this article , the analysis of dielectric losses obtained through the coldwave field analysis of anisotropic conducting tape helix supported by lossy Dielectric rods in travelling wave tubes (TWT) is presented.
Abstract: This paper presents the analysis of dielectric losses obtained through the coldwave field analysis of anisotropically conducting tape helix supported by lossy dielectric rods in travelling wave tubes (TWT). The electromagnetic field expressions are derived through field approach using Maxwell's equations and vector Helmholtz's equations by solving the complex constants through boundary conditions. Through the application of lossy dielectric permittivity in the resultant axial electric field, the shunt capacitance and the shunt conductance per unit length are obtained. The presence of lossy dielectric support rods in the slow wave structure (SWS) results in attenuation of the propagating electromagnetic wave. The attenuation constant obtained through the present analysis has been compared with the published models and experimental results. The effect of the frequency and temperature is also studied for X-Ku band and Q- band travelling wave tube amplifiers.
25 Apr 2023
TL;DR: In this paper , the analysis of dielectric losses obtained through the coldwave field analysis of anisotropic conducting tape helix supported by lossy Dielectric rods in travelling wave tubes (TWT) is presented.
Abstract: This paper presents the analysis of dielectric losses obtained through the coldwave field analysis of anisotropically conducting tape helix supported by lossy dielectric rods in travelling wave tubes (TWT). The electromagnetic field expressions are derived through field approach using Maxwell's equations and vector Helmholtz's equations by solving the complex constants through boundary conditions. Through the application of lossy dielectric permittivity in the resultant axial electric field, the shunt capacitance and the shunt conductance per unit length are obtained. The presence of lossy dielectric support rods in the slow wave structure (SWS) results in attenuation of the propagating electromagnetic wave. The attenuation constant obtained through the present analysis has been compared with the published models and experimental results. The effect of the frequency and temperature is also studied for X-Ku band and Q- band travelling wave tube amplifiers.
References
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TL;DR: The dispersion equation for electromagnetic waves guided by an open tape helix for the standard model of an inflitesimally thin and perfectly conducting tape is derived from an exact solution of a homogeneous boundary value problem for Maxwell's equations as mentioned in this paper.
Abstract: The dispersion equation for electromagnetic waves guided by an open tape helix for the standard model of an inflnitesimally thin and perfectly conducting tape is derived from an exact solution of a homogeneous boundary value problem for Maxwell's equations. A numerical analysis of the dispersion equation reveals that the tape current density component perpendicular to the winding direction does not afiect the dispersion characteristic to any signiflcant extent. In fact, there is a signiflcant deviation from the dominant-mode sheath- helix dispersion curve only in the third allowed region and towards the end of the second allowed region. It may be concluded that the anisotropically conducting model of the tape helix that neglects the above transverse-current contribution is a good approximation to the isotropically conducting model that takes into account this contribution except at high frequencies even for wide tapes.
16 citations
"Wave propagation characteristics in..." refers background in this paper
...Almost all published derivations on tape helix dispersion characteristics, until the work of Kalyanasundaram et al.[1] in 2009,were based on an a’priori assumption about the behaviour of the tape current distribution near the edges or an ad hoc assumption about the tape-current distribution....
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...The model proposed in [1] was extended for the practically relevant case of a tape helix [2] supported inside a coaxial perfectly conducting cylindrical shell by symmetrically disposed wedge-shaped (see Fig....
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...Introduction Almost all published derivations on tape helix dispersion characteristics, until the work of Kalyanasundaram et al.[1] in 2009,were based on an a’priori assumption about the behaviour of the tape current distribution near the edges or an ad hoc assumption about the tape-current distribution....
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TL;DR: In this article, a dielectric-loaded tape helix enclosed in a coaxial perfectly conducting cylindrical shell was analyzed for guided electromagnetic wave propagation, and the dispersion equation was solved to yield the solvability condition for an infinite system of linear homogeneous algebraic equations.
Abstract: The practically important case of a dielectric-loaded tape helix enclosed in a coaxial perfectly conducting cylindrical shell is analysed in this paper. The dielectric-loaded tape helix for guided electromagnetic wave propagation considered here has infinitesimal tape thickness and infinite tape-material conductivity. The homogeneous boundary value problem is solved taking into account the exact boundary conditions similar to the case of anisotropically conducting open tape helix model [1, 2]. The boundary value problem is solved to yield the dispersion equation which takes the form of the solvability condition for an infinite system of linear homogeneous algebraic equations viz., the determinant of the infiniteorder coefficient matrix is zero. For the numerical computation of the approximate dispersion characteristic, all the entries of the symmetrically truncated version of the coefficient matrix are estimated by summing an adequate number of the rapidly converging series for them. The tape-current distribution is estimated from the null-space vector of the truncated coefficient matrix corresponding to a specified root of the dispersion equation.
11 citations
"Wave propagation characteristics in..." refers background in this paper
...The model proposed in [1] was extended for the practically relevant case of a tape helix [2] supported inside a coaxial perfectly conducting cylindrical shell by symmetrically disposed wedge-shaped (see Fig....
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