RADIO PHYSICS AND RADIO ASTRONOMY

PACS number: 41.20.-q 

Purpose: Investigation of a shielded disk dielectric resonator (DR) having a high Q-factor and improved spectral characteristics.

Design/methodology/approach: The experimental study of energy characteristics of the investigated shielded resonator was carried out by using the PNA–L Network Analyzer N5230a 10 MHz 40 ÷ GHz Agilent Technologies. Spectral characteristics of the resonance system were analyzed using the panoramic voltage standing wave ratio meter R2-65. The modes excited in the shielded DR were identified by investigating the distribution of the electric component of the resonant field along the radial coordinate. For rapid and accurate numerical simulation of the investigated resonance system, the CST Microwave Studio 2013 software package was used.

Findings: The peculiarities of excitation of the lowest radial HE3111 whispering gallery mode in the shielded disk DR with the help of a waveguide coupling element are considered. It is shown that in the region of the dielectric–air interface, the resonant field is characterized by the greatest intensity. The maximum excitation efficiency of the whispering gallery modes in the DR is achieved when the coupling element is located on the border of the dielectric disk. It is established that the field of the whispering gallery mode in an open disk DR is concentrated mainly in the material the resonator is made of. In a shielded DR, the resonant field shifts to the air gap region. In this case, the ohmic losses in the metal shield walls are small, since the intensity of the resonance field at the air–metal interface is insignificant. Due to this, the loaded Q-factor of the shielded DR increases by more than 1.9 times in comparison with the open DR.

Conclusions: A shielded disk DR under certain excitation conditionshas a high value of the loaded Q-factor and the rarefied oscillation spectrum. This makes it promising for the use in frequency stabilization schemes for millimeter wave solid-state sources.

Key words: shielded dielectric resonator, whispering gallery modes, Q-loaded, rarefied spectrum

Manuscript submitted 17.10.2017



Radio phys. radio astron. 2017, 22(4): 310-318

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