In the manufacturing process beam pipes acquire a structure on their inner walls with a roughness depth in the order of typically 0.5 μm rms. This surface structure is polarised by the beam and can be interpreted as an artificial dielectric. The thin dielectric layer model shows, that for rough tubes there is exactly one synchronous mode, the so called “rough tube mode” (normally in the THz reg...

The target scattering characteristics in microwave band are necessary to be researched for Orbital-Angular-Momentum (OAM) wave-based radar applications. A theoretical description of electromagnetic (EM) from a typical by OAM waves is proposed this paper. First, decomposed into plane the spectral domain with different elevation and azimuth angles. Then, form each wave determined through coordina...

It is shown how the Debye rotational diffusion model of dielectric relaxation of polar molecules (which may be described in microscopic fashion as the diffusion limit of a discrete time random walk on the surface of the unit sphere) may be extended to yield the empirical Havriliak-Negami (HN) equation of anomalous dielectric relaxation from a microscopic model based on a kinetic equation just a...

Absfract-A new model for the aperture admittance of open-ended waveguide structures radiating into a homogeneous, lossy dielectric is presented. The model is based on the physical and mathematical properties of the driving point admittance of passive, stable one-port networks. The model parameters, which depend upon the geometry of the waveguide and aperture, are determined from a relatively sm...

Asymmetric directional coupling between a hybrid plasmonic waveguide with subwavelength field confinement and a conventional dielectric waveguide is investigated. The proposed hybrid coupler features short coupling length, high coupling efficiency, high extinction ratio, and low insertion loss; it can also be integrated into a silicon-based platform. This coupler can be potentially adopted for ...

This paper examines in detail the characteristics of a leaky Lamb wave propagating in a piezoelectric plate immersed in a dielectric or conductive fluid. The analysis is based on the partial wave analysis and its numerical calculations. Some corrections have been made so that both the changes in phase velocity and the wave attenuation of leaky Lamb waves caused by fluid’s mechanical, dielectric...

We have measured the temperature dependence of the microwave surface impedance Zs5Rs1ivm0l of two c-axis oriented MgB2 films employing dielectric resonator techniques. The temperature dependence of the magnetic-field penetration depth l determined by a sapphire dielectric resonator at 17.9 GHz can be well fitted from 5 K close to Tc by the standard BCS integral expression assuming the reduced e...

Hyperbolic materials enable numerous surprising applications that include far-field subwavelength imaging, nanolithography, and emission engineering. The wavevector of a plane wave in these media follows the surface of a hyperboloid in contrast to an ellipsoid for conventional anisotropic dielectric. The consequences of hyperbolic dispersion were first studied in the 50's pertaining to the prob...

We describe an innovative implementation of the Shack-Hartmann wave-front sensor that is designed to correct the perspective elongation of a laser guide beacon in adaptive optics. Subapertures are defined by the segments of a deformable mirror rather than by a conventional lenslet array. A bias tilt on each segment separates the beacon images on the sensor's detector. One removes the perspectiv...