Publication de 12 numéros par an
ISSN Imprimer: 0040-2508
ISSN En ligne: 1943-6009
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AZIMUTH MODES IN QUASI-OPTICAL DIELECTRIC RESONATOR WITH DIFFRACTION GRATING
RÉSUMÉ
Quasi-optical dielectric resonators are widely used in microwave engineering as the components of source control systems and as well as in the facilities for study of electro-physical properties of substance. High quality and convenience in service are main positive properties of these resonators. But the frequency intervals between azimuth modes is notably small. The latter circumstance gives a high probability of an arbitrary frequency leaping from the operational mode to adjacent ones. The aim of our investigation is to study theoretically and experimentally a possibility of the spectrum rarefaction of the forced azimuth «whispering gallery» modes of a disk dielectric resonator. Three resonator types are investigated - the dielectric resonator without any additional components, dielectric resonator with conducting screen on the cylindrical surface and dielectric resonator with diffraction grating consisting of the conducting of the conducting strips situated on the lateral cylindrical surface. Computer-aided simulation was carried out by the finite-difference in time-domain (FDTD) method. Experimental study was performed by the standard VSWR-measurer at 8...12 GHz frequency band. By means of computer and full-size experiments there were received the spectra of «whispering gallery» modes of half disk resonator, resonator covered by screen, and resonator with the diffraction grating on a lateral surface. The azimuth mode excitation at one frequency with suppressing of adjacent modes no less than by 15...20 dB at the filling coefficient of diffraction grating being equal to θ =0.3 has been derived. FDTD-technique is an adequate grid method for simulation of the forced oscillations in the systems where oscillatory processes are due to both diffraction and the forming of standing waves. Single mode excitation had been accomplished owing to using a diffraction grating in disk dielectric resonator.