Tatarchuk D. Controllable composite structures of the microwave range

The work is devoted to the using of the composite structures for creating controlled microwave devices. The work shows that the use of such structures can significantly extend the functionality of microwave devices. The aim of the work is to develop the theory of composite materials to create a basis for the implementation of new frequency-selective and phase-rotating devices based on composite, semiconductor and thin dielectric resonant structures, as well as to improve microwave methods for dielectric materials, including thin films. When performing the work the following results were obtained: 1. The theory of composite materials is developed. Analytical expressions for the calculation of the temperature coefficients of effective dielectric constant and effective tangent of dielectric loss angle of composite dielectric-metal materials were first obtained, which allows calculating the temperature properties of such composites. 2. The theory of composite materials is applied to the controlled frequency-selective planar structures and based on it the calculation method of the controlled frequency-selective planar structures characteristics is developed and experimentally confirmed, which allows to accelerate the design process of the controlled frequency-selective devices and phase-rotating devices. 3. New principles for the resonant frequencies control of the dielectric resonators by changing the angle of rotation of the resonator with respect to the wide wall of the waveguide were proposed for the first time, which made it possible to develop new designs of controlled filters and phase rotators. Precise control of the position of the resonator in this case is carried out using a stepper motor controlled by a microprocessor, which allows to eliminating such disadvantage of traditional electromechanical control as hysteresis. 4. The design of the “cymbal”-type piezoelectric transducer was improved by replacing the continuous piezo-plate with two counter-plates, which reduced the nonlinearity of its deformation characteristic. 5. For the first time, a method of controlling the characteristics of semiconductor planar frequency-selective microwave devices is proposed by changing the configuration of conductive regions by an optical method, which creates the basis for the development of fundamentally new designs of frequency-selective and phase-rotating microwave devices with optical control. 6. Based on the theory of composite materials and the results of the study of thin dielectric resonators, the Krupka’s method was modified to determine the dielectric constant and the tangent of the dielectric loss angle of thin films. The proposed method allows to measure the parameters of film materials in the thickness from tens of nanometers to several micrometers. 7. A new method of investigation of the properties of anisotropic materials is proposed when using the test sample as a thin dielectric resonator The topic of the dissertation is a continuation of many years scientific activity of the Department of Microelectronics staff in the field of finding the new approaches to the design of microwave microelectronic devices in order to improve their characteristics. The results of theoretical and experimental studies obtained in the work were used in the implementation of the 9 state projects, and were applied in the educational process of the Department of Microelectronics of the National Technical University of Ukraine “KPI them. Igor Sikorsky “ The developed methods of measuring the parameters of microwave materials were used in the research at the Donetsk Institute of Physics and Technology of the NAS of Ukraine and the Institute of General and Inorganic Chemistry of the NAS of Ukraine.