General expressions for the coupling coefficient, quality and filling factors for a cavity with an insert using energy coupled mode theory

Elnaggar, Sameh Y.; Tervo, R.; Mattar, Saba M.

doi:10.1016/j.jmr.2014.01.018

Cited by 15 publications

(16 citation statements)

References 30 publications

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“…For samples which have relatively low permittivity values, the walls of the cylindrical cavity can have a significant effect. Moreover, the cavity modes can interact with the dielectric mode [7], [8]. The efficiency of wireless power transfer via strong inductively-coupled resonant coils can also be affected by metallic planes [1], [2].…”

Section: Theorymentioning

confidence: 99%

“…The total electric field is the vector sum of the fields, of all orders. Thus (7) where (8) for and (9) for . is distance between the two planes.…”

Section: Theorymentioning

confidence: 99%

“…This can be explained by noting that in order to calculate the frequencies, ECMT uses the mode, while ECMT-I uses the mode which, by referring to (2) and noting that , has a higher frequency value. When the dielectric is close to the wall, the electric field of the cavity's mode is small [8]. The coupling coefficient is the overlap of the electric fields of the cavity and the dielectric resonator and hence is small close to the wall.…”

Section: A Dielectric-cavity Interactionmentioning

confidence: 99%

“…The first is that of a dielectric resonator interacting with an enclosing cavity. In previous work, the interaction between the dielectric resonator and the cavity was studied where the dielectric resonator was installed in the cavity center and hence its field values are small near the walls [7], [8]. In the current work, the effect of the walls on the coupled frequencies is taken into account.…”

mentioning

confidence: 98%

“…Using the coupled mode equations, the eigenmodes of an electron spin resonance probe, which consists of a dielectric resonator inserted in a cavity center were found [7]. Other field-dependent parameters, such as the quality factor, the filling factor, and the resonator efficiency, were calculated [8], [9]. The same approach was generalized to explain the behavior of double split-ring resonators.…”

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confidence: 99%

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Coupled Mode Theory Applied to Resonators in the Presence of Conductors

Elnaggar

Tervo

Mattar

2015

IEEE Trans. Microwave Theory Techn.

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Using the method of images, Energy Coupled Mode Theory (ECMT), a coupled mode equation in the frequency domain, is extended to deal with important cases where resonators are in close proximity to conducting surfaces. Depending on the type of conductors and the orientation of the resonators, the method of images determines the relative phases of the images. Using the formed images, the coupled frequencies and fields can be determined by applying ECMT. Two cases are studied. In the first case, it is shown that a dielectric resonator inserted in a cavity couples with both the mirror image and the cavity. The frequency behavior is described by the interaction with the image which counteracts that with the cavity. The second case is that of resonators sandwiched between conducting plates. It is shown that an infinite array of stacked images is formed. The coupling of the resonator with its images determines the coupled frequencies and fields. In this context, the main advantage of ECMT is its ability to separate the effects of the walls from the uncoupled system. This means that the system parameters are independent of the separation distances and/or the type of conductors, which renders the post processing analyses easier and predictable. Provided that the behaviors of the uncoupled resonators are known, ECMT is general and can be applied to more complex systems.

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Section: Theorymentioning

confidence: 99%

“…The total electric field is the vector sum of the fields, of all orders. Thus (7) where (8) for and (9) for . is distance between the two planes.…”

Section: Theorymentioning

confidence: 99%

Section: A Dielectric-cavity Interactionmentioning

confidence: 99%

mentioning

confidence: 98%

mentioning

confidence: 99%

See 3 more Smart Citations

Coupled Mode Theory Applied to Resonators in the Presence of Conductors

Elnaggar

Tervo

Mattar

2015

IEEE Trans. Microwave Theory Techn.

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Modes and Fields of Two Stacked Dielectric Resonators in a Cavity of an Electron Paramagnetic Resonance Probe

Mattar

Elnaggar

2017

Appl Magn Reson

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EPR Uniform Field Signal Enhancement by Dielectric Tubes in Cavities

Hyde

Mett

2017

Appl Magn Reson

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The dielectric tube resonator (DTR) for EPR spectroscopy is introduced. It is defined as a metallic cylindrical TE011 microwave cavity that contains a dielectric tube centered on the axis of the cylinder. Contour plots of dimensions of the metallic cylinder to achieve resonance at 9.5 GHz are shown for quartz, sapphire, and rutile tubes as a function of wall thickness and average radius. These contour plots were developed using analytical equations and confirmed by finite element modeling. They can be used in two ways: design of the metallic cylinder for use at 9.5 GHz that incorporates a readily available tube such as a sapphire tube intended for NMR, or design of a custom procured tube for optimized performance for specific sample-size constraints. The charts extend to the limiting condition where the dielectric fills the tube. However, the structure at this limit is not a dielectric resonator due to the metal wall and does not radiate. In addition, the uniform field (UF) DTR is introduced. Development of the UF resonator starting with a dielectric tube resonator is shown. The diameter of the tube remains constant along the cavity axis, and the diameter of the cylindrical metallic enclosure increases at the ends of the cavity to satisfy the uniform field condition. This structure has advantages over the previously developed UF TE011 resonators: higher resonator efficiency parameter Λ, convenient overall size when using sapphire tubes, and higher quality data for small samples. The DTR and UF DTR structures fill the gap between free space and dielectric resonator limits in a continuous manner.

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General expressions for the coupling coefficient, quality and filling factors for a cavity with an insert using energy coupled mode theory

Cited by 15 publications

References 30 publications

Coupled Mode Theory Applied to Resonators in the Presence of Conductors

Coupled Mode Theory Applied to Resonators in the Presence of Conductors

Modes and Fields of Two Stacked Dielectric Resonators in a Cavity of an Electron Paramagnetic Resonance Probe

EPR Uniform Field Signal Enhancement by Dielectric Tubes in Cavities

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