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Dielectric resonators are key components for many microwave and millimetre wave applications, including high-Q filters and frequency-determining elements for precision frequency synthesis. Multilayered, bulk low-loss crystal and polycrystalline dielectric structures have become very important for designing these devices. Proper design requires careful electromagnetic characterisation of low-loss material...
We developed an effective technique for phase synchronization of a cryogenic microwave oscillator. The achieved quality of phase synchronization is a few milliradians. It enables accurate measurements of extremely weak phase fluctuations expected from the next generation of frequency stabilized microwave oscillators based on the cryogenically cooled sapphire dielectric resonators.
We report on the demonstration of a resonator based on electromagnetic field confinement in a hollow-core by an out-of-plane 2D photonic band-gap (PBG) crystal cladding. The resonator is designed to concentrate the energy within an air region in the center of the resonator and away from the cavity walls to minimize conductor losses. In contrast with in- plane 2D PBG crystal devices, the PBG crystal...
The whispering gallery modes have been used to characterize the effect of the light on gallium arsenide and gallium phosphide placed in darkness at 50 K at frequencies respectively equal to 18.94 GHz and 11.54 GHz. The experiment shows a change in the polarization state of the semiconductor, which is consistent with a free electron-hole creation/recombination process. The permittivity and the loss...
This paper describes the use of a new resonator using a hybrid Bragg mode (HBM) with azimuthal variations greater than zero. Usually Bragg modes require a pure transverse electric mode with no azimuthal variations and only electric field component, E0. The mode is both Bragg-like, (Er is tangential to all dielectric boundaries) and also whispering gallery-like, (possesses azimuthal variations). This...
The complex permittivity of bulk crystals of semiinsulating gallium arsenide (GaAs) and gallium phosphide (GaP) were measured over the frequency range from 4 to 30 GHz and at temperatures from 30 up to 300 K employing whispering-gallery-mode (WGM) and quasi-TE0np-mode dielectric-resonator techniques. At temperatures about 40 K, dielectric loss tangent values were below 10 -6 for GaAs and below 10...
The author's report on the observation of a new type of Bragg confined mode in a dielectric loaded cavity. The structure is built from a hollow single layer dielectric cylinder loaded in a silver platted copper cavity. A resonance was observed at 13.4 GHz with an unloaded Q-factor of order 2??105, which is more than a factor of 6 above the dielectric loss limit. Previously such modes have only been...
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