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A simple non-Maxwellian model is used for designing Bragg reflectors of cylindrical geometry and arbitrary thicknesses for the horizontal or cylindrical dielectric reflectors. Results suggest the achievement of an unloaded Q-factor of 234,000 at 9.7 GHz for the fundamental mode.

The application of one of the first few composite cylindrical T[E.sub.0n1] modes for measurements of the complex permittivity of ferroelectrics based on rigorous electromagnetic analysis of the structure is reported. Variable temperature measurements are performed on a Pb[Mg.sub.1/3][Nb.sub.2/3][O.sub.3] (PMN) ceramic sample, and the measured complex permittivity has shown good agreement with the results of measurements obtained on the same sample at lower frequencies.

The anisotropic loss tanget is determined in monocrystalline sapphire for components parallel and perpendicular to the crystal axis, using the whispering gallery (WG) mode method. Sapphire dielectric material from three different manufacturers is compared over the 270-345 K temperature range and the 5-16 GHz frequency range.

A Fabry-Perot resonator operating at 39 GHz, with two pairs of quarter-wavelength single-crystal quartz Bragg reflectors is realized. Good agreement between theoretical and experimental resonant frequency and Q-factors is obtained while thermal compensation of the resonant frequency of the Fabry-Perot is proposed employing rods and cylinders made of metals with different thermal expansion coefficients.

The concept of the spherical Bragg reflector (SBR) resonator is introduced. The resonator is made from multiple layers of spherical dielectric, loaded within a spherical cavity, and is designed to concentrate the energy within the central region of the resonator and away from the cavity walls to minimize conductor losses.

New measurements of dielectric properties of Lanthanum gallium silicate (Langasite or LGS) conducted with the whispering-gallery mode technique at microwave frequencies is calculated along with the first measurements of the two independent components of the imaginary part of the permittivity tensor. It appears LGS is a relatively high-loss dielectric material compared with sapphire or quartz.

The frequency stability of microwave oscillators have improved considerably depending on very low loss, single crystals with frequency temperature self compensation of the resonance mode. From the isotropic materials like the calcium and lithium fluoride only one form of resonance is selected which shows whispering gallery (WG) mode electromagnetic field structure.

A new approach for designing a high-Q microwave resonator with low spurious mode density is described and discussed.

A new technique for compensating the frequency-temperature dependence of high-Q monolithic sapphire dielectric resonators near liquid nitrogen temperature is shown. This is accomplished by doping monocrystalline sapphire with Ti3+ ions. Calculations showed that a Ti3+ doped sapphire resonator may have its frequency-temperature dependence nulled anywhere between 4 and 80 K depending on the concentration of the Ti3+ ions.

Research was conducted to study a sapphire-rutile composite microwave dielectric resonator obtained from a cylindrical sapphire monocrystal that supported two thin disks of monocrystal rutile at the end. A sweep oscillator was used to determine the mode frequencies of the resonator while the N1 E-mode family frequency was represented as a function of temperature. Results indicated that the resonator can be utilized in the construction of temperature stable microwave oscillators that operate above liquid helium temperatures.