Waveguides, dielectric

There are two mechanisms that causes losses in waveguides dielectric losses and metal losses. In both cases, these losses cause the amplitudes of the propagating modes to decay as exp(—az), where a is the attenuation constant, measured in neper/meter. Typically, the attenuation constant is considered as the sum of two components a = cKdie + met) where aaie and aniet arc the dielectric and metal attenuation... 

Microwaves from the waveguide are coupled into the resonator by means of a small coupling hole in the cavity wall, called the iris. An adjustable dielectric screw (usually machined from Teflon) with a metal tip adjacent to the iris pennits optimal impedance matching of the cavity to the waveguide for a variety of samples with different dielectric properties. With an appropriate iris setting the energy transmission into the cavity is a maximum and simultaneously reflections are minimized. The optimal adjustment of the iris screw depends on the nature of the sample and is found empirically. 

Figure C2.15.12. (a) TE and (b) TM modes for tire dielectric planar waveguide.

D. Marcuse in Theory of Dielectric Waveguides,, Chapter I, Academic Press. New York 1974. 

Figure 1. Optical waveguides - a) dielectric slab waveguide, b) dielectric strip waveguide, and c) dielectric channel waveguides, d) optical fiber, e) metal-clad dielectric waveguide, and f) (degenerated) metal-dielectric waveguide.

Six successive units are visible on the Fig. 1.19 (left) and they are set to obtain the heating of reactants in a vertical glass pipe. Each applicator is constituted by a parallelepiped metallic box (200 x 200 x 300 mm3). The reactor is a dielectric pipe with diameter between 70 and 100 mm. This pipe passes through the box following the electric field direction within the excitation waveguide. This waveguide can be seen... 

Yariv, A., Universal relations for coupling of optical power between microresonators and dielectric waveguides, Electron. Lett. 2000, 36, 321 322... 

The other platform is dielectrics, for example, silicon dioxide, silicon nitride, silicon oxynitride, tantalum pentoxide, and titanium dioxide. They can be deposited by various methods, such as plasma-enhanced chemical vapor deposition, thermal evaporation, electron-beam evaporation, and sputtering. There are a number of dielectrics with refractive indices ranging from 1.45 to 2.4, facilitating diverse waveguide designs to satisfy different specification. Dielectrics have two other... 

The fundamental mode of a uniform lossless dielectric waveguide and, in particular, an MNF exists independently of its thickness. However, in practice, wave-guiding is limited by losses due to material absorption and geometric nonuniformities. For a very thin MNF, the transmission loss is primarily determined by input and output losses, which, in practice, cannot be reduced significantly11 64. As an example, Refs. 11 and 13 theoretically explored an MNF with adiabatically... 

For waveguide modes in a pure dielectric structure, Nm is nmax = Max c, ns at dF = (/cutoff and nF at dF > oo. The so-called cut off thickness, (/cutoff is defined as the film thickness at which the field s propagation angle in the film gets... 

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