Circuital analysis of a coaxial re-entrant cavity for performing dielectric measurement

Full-Wave Analysis of Dielectric-Loaded Cylindrical Waveguides and Cavities Using a New Four-Port Ring Network

“…Re-entrant coaxial waveguide and its circuit segmentation. By short-circuiting (perfect electric walls are assumed in the simulation) both ends (ports 1 and 2), and imposing resonant condition [57], this structure becomes a re-entrant cavity, which is a common device for measuring the complex permittivity of dielectric materials, as described in [29,[58][59][60][61][62].…”

“…Short-circuits can be modeled either as perfect conductors (PEC) or conductors with a finite conductivity, as described previously in the Theory section. Resonant frequencies and quality factors have been calculated using the resonant condition [57] and the complex resonant frequency concept [56]. Table I shows the first two resonant frequencies and Qfactors corresponding to the TM 0np (TM 010 and TM 020 ) modes of a cylindrical cavity coaxially-loaded with dielectric materials of different permittivity, and first resonant mode TM 010 when the dielectric is inside a dielectric tube.…”

Measurement of dielectric properties at high-temperatures in real-time with cylindrical cavity

“…At the lowest temperature, the exact permittivity has been calculated by other methods and the value obtained with mode-matching method combined with circuit theory [7,8] is £r=9. 77-1"0.…”

Finding resonant frequencies for high loss dielectrics in cylindrical cavities

“…Figure shows a 2D image of the problem to be solved by circuit analysis (applying the resonant condition described in ) with the location of the zeros that are the complex resonant frequencies for the high loss dielectric case, that is, ε r1 = 5·(1 − j· 10 −1 ). It is clear that the zeros are the complex resonant frequencies, defined as , where the real part is the resonant frequency and the imaginary part is related with the Q ‐factor as shown in .…”

“…The remarkable difference is that the values obtained by the analytical method with APM are direct and no roots are lost, while the numerical procedure does not always provide the appropriate root, as shown in the next paragraphs, where Figures 2 and 3 are explained to obtain a seed for the circuit method. Figure 2 shows a 2D image of the problem to be solved by circuit analysis [2] (applying the resonant condition described in [1]) with the location of the zeros that are the complex resonant frequencies for the high loss dielectric case, that is, e r1 5 5Á(1 2 jÁ10 21 ). It is clear that the zeros are the complex resonant frequencies, defined as X5f r Á 11j= 2 Á Q ð Þ ð Þ , where the real part is the resonant frequency and the imaginary part is related with the Q-factor as shown in [14].…”