Zinher Y. Frequency filters based on three-dimensional electromagnetic-crystal inhomogeneities

The thesis proposed microstrip low-pass filters based on three-dimensional (3D) electromagnetic-crystal inhomogeneities (ECI). Comparison of the calculated amplitude-frequency characteristics of quasi-lumped reactive elements based on traditional structures and ECI has been made. The frequency response of quasi-lumped reactive elements on the basis of ECI is noticeably closer to the frequency response of the lumped elements. The cutoff frequency of the suppression band, determined by the frequency of the first minimum of the frequency response, is for ECI three times higher. Characteristics are calculated using the 3D electromagnetic modeling environment CST Microwave Studio. The proposed ECI, which combining inductive and capacitive elements. Such ECI called combined. The structure of low-pass filters based on single and combined ECI are presented. The calculated and experimental parameters and the frequency response of the filters are given, illustrating a noticeable decrease in the size and improvement of the characteristics in the suppression band as compared with the filter of the traditional structure. A comparison is made of the results of three and one-dimensional modeling of microstrip low-pass filters with traditional designs and based on 3D ECI. The one-dimensional model is a non-uniform transmission line with equivalent parameters. Filters based on different impedance sections of the microstrip line and with a capacitive stub are considered. The possibility of using a one-dimensional model as a model of the first approximation is substantiated. The design differences between traditional two-dimensional and 3D capacitive stubs are considered and their capacitances are compared. The design to reduce the effect of the associated capacitances is proposed.