Serhiienko P. Micromechanically tunable microwave resonators based on strip lines

Ph.D. thesis is devoted to investigation of the influence of geometrical and electro physical parameters of tunable microstrip resonators on its resonant frequency, its quality factor and coupling coefficient between resonator and microstrip line. The method of effective permittivity, characteristic impedance and loss of the microstrip line with tunable air heterogeneity determination with scattering matrix elements approximation which derived from finite element method results is proposed. Verification of approximation and experimental data is performed. Influence of microstrip line with air heterogeneity physical and topological parameters on its equivalent parameters is analyzed. Micromechanically tunable microstrip resonance elements are developed and experimentally investigated. Models of microstrip resonance elements which simplify the calculation of its characteristics are created. Influence of air heterogeneity on resonance frequency, unloaded quality actor and coupling coefficient of tunable microstrip stub and ring resonators are analyzed. Micromechanically tunable coplanar stub resonator model is proposed and simulated. Influence of geometrical and electrophysical resonators parameters and external factors on resonance frequency, unloaded quality factor and coupling coefficient of tunable microstrip stub and ring resonators are investigated. Resonance frequency sensitivity dependencies to the resonator parameters deviation are obtained. With sensitivity dependencies resonance frequency temperature coefficient and resonance frequency experimental determination error are calculated. Resonators based on microstrip lines with tunable air heterogeneity provide smooth tuning in the wide frequency range without unloaded quality factor deterioration, which provide the opportunity to reduce the cost and weight and size parameters of existing selective devices working in different frequency ranges.