V. V. Kutuzov

Whispering gallery modes induced in a partly shielded hemispherical dielectric resonator

Whispering gallery modes induced in a partly shielded hemispherical dielectric resonator by lumped radiation sources were experimentally studied for the symmetric and asymmetric arrangement of the hemisphere relative to the cylindrical metal shield. The oscillation mode characteristics are presented for the shielded hemispherical resonator and an analogous open dielectric resonator. The proposed resonator is a promising device for the creation of highly stable solid-state millimetric wave oscillators.

Slot line excitation of whispering gallery oscillations in shielded dielectric resonators

Electrodynamic characteristics of a half-disc shielded dielectric resonator operating in the 8-mm wavelength range have been investigated experimentally. A slot line was proposed for the excitation of whispering gallery modes in such resonator. It has been found out that the proposed excitation technique is effective and allows the high-Q oscillations of higher orders to be excited in a shielded dielectric resonator without additional energy losses. The partial shielding of the resonator in question was proposed for its spectrum rarefaction.

Millimeter-wave whispering gallery modes in an ellipsoidal dielectric resonator with a small ellipticity

It is found that, when the shape of a dielectric sphere (hemisphere) operating under the whispering gallery mode conditions is perturbed by a surface curvature gradient (ellipticity), the unloaded Q factor of the sphere degrades and its resonance frequencies change. It is shown theoretically and experimentally that an elliptic irregularity removes frequency degeneracy of whispering gallery modes at millimeter waves.

High-Q whispering-gallery oscillations in a shielded spherical dielectric cavity

Results are presented of theoretical and experimental investigations of whispering-gallery oscillations in a shielded isotropic layered spherical dielectric cavity. Oscillations whose Q factor is two orders of magnitude higher than that of the oscillations of an open dielectric sphere are studied. Intermode interaction is observed between various cavity oscillation modes.

Excitation of whispering gallery modes in shielded dielectric resonators by “slot-line”

Open dielectric resonators (DRs) as disk and ball with whispering gallery modes (WGMs) have well known advantages such as a high value of Q-factor in millimeter band of wavelength. However they have disadvantages when used in specific devices and appliances. 1. The open nature of the dielectric resonator is a source of electromagnetic noise interference. The shielding of DRs is the main method of combating such injurious electromagnetic effects. However, the shielding causes a significant concentration of the oscillation spectrum. At the same time the so-called ray modes can be excited in the shielded DRs with the WGMs. 2. It is known that the use of local elements of excitation placed in the resonator field is the most effective method for excitation of the WGMs in the DRs. However, in this case, the Q-factor is decreased due to high radiation losses at the local element of mode excitation. The solution of these two problems is the aim of this work.

Dielectrometer measuring cell for investigation of liquids with high losses and high dielectric constant designed in form of the two - layer semispherical Teflon resonator

During the last time open dielectric resonators (DR) excited on whispering-gallery type waves due to their high Q-factor on the higher modes are used to investigate the dielectric properties of not only solid substances but also of liquids. For these purposes in the first experiments DR (which was used as measuring cell) being immersed directly in tested liquid. The investigated liquid influenced on external caustic of DR that led to frequency sift and changes of resonator Q factor. New achievement in creation of the dielectrometer measuring cells have appeared after the creation of the resonant structures in which certain geometrical parts of resonators are used. At first, such DR were created with metal mirrors. The subsequent researches [1] have shown that oscillations exist also without a mirror, which itself leads to condensate of a spectrum and reduction of the quality of resonator.

Cavity method for determination of dielectric characteristics of fine granular materials in 8-mm range of wavelengths

A resonator method and results of investigation of dielectric characteristics of bulk materials in the 8-mm range of wavelengths are presented. Accuracy of experimental estimation of dielectric constant and loss-angle tangent δ of mixture of sand and cement are investigated in the process of manufacturing of a dielectric resonator from the probed material and exciting on modes of “whispering gallery”.

Hemispherical dielectric resonator with concentric hemispherical hollow for liquid dielectrics investigations

A new measuring cell is suggested in order to investigate dielectric properties of liquids with great losses.

Peculiarities of the excitation of whispering gallery waves in the hemispherical dielectric resonator

The carried out investigations of the whispering gallery mode fields in a hemisphere by a local radiant arranged on a mirror and, not having central symmetry, have shown an opportunity of preferred excitation of waves of one type E or H. It allows a little to rarefy a spectrum of excited oscillations, having restricted one of the modes, and more effectively to use a resonance-frequency behaviour of a hemisphere as resonant system.

Peculiarities of H-mode oscillation on the dielectric hemisphere form resonator

This work presents new experimental results of H-mode whispering gallery in the hemisphere dielectric resonators. Peculiarity of electromagnetic field structure of H-mode oscillations, which has been experimentally obtained, and excitation of whispering gallery mode oscillations in hemisphere in a form of equatorial belts are presented.