Development of theory and circuit solutions of non-minimum-phase planar filters with mixed couplings for telecommunications

The object of the study is non-minimal-phase radio-wave filters of planar design (stripline and microstrip), which, in addition to reflection-type resonators, contain through-type resonators, and which use mixed electromagnetic couplings between resonators.
The subject of research is the influence of mixed electromagnetic coupling on the frequency characteristics of more complex non-minimal-phase planar filters, which should lead to the creation of a new theory.
According to the results of research, the theory of planar non-minimal-phase filters of the third and fourth order for telecommunications with different frequency responses was created. Techniques for constructing these filters have been developed, which do not use low-frequency prototypes, but allow direct calculation of circuit elements. New designs of planar band-pass filters (BPF) with cross couplings, which are characterized by a wide variety of implemented frequency responses, are proposed and analyzed. Along with increased one-sided selectivity, they may have a symmetric frequency response with attenuation pole located to the right and left of the bandwidth. The basis of the filters are pairs of closely spaced step-impedance resonators (SIR), the electromagnetic connection between which is mixed, both capacitive and inductive. Experimental samples of new planar non minimal-phase filters of the third and fourth order for telecommunications are obtained, and the results of their experimental research, which confirm the theoretical provisions of the theory.
As a result of the work, 11 articles were published in IEEE journals belonging to the first quartile of Q1, 2 articles in journals belonging to the second quartile of Q2. A total of 18 articles have been published, which are indexed in the Scopus database. 8 papers have been published in the materials of international IEEE conferences, which are part of the Scopus database. According to the results of the research, Book Chapter was written: “Planar bandpass filters with mixed couplings”. Lecture Notes in Networks and Systems, 2021, which will be used to prepare graduate students in 172 Telecommunications and Radio Engineering. The work was attended by two PhD graduates and a candidate of technical sciences, whose dissertations are close to completion.
During the research period, the total h-index performers of the project increased from h = 13 to h = 30, which contributes to the improvement of Igor Sikorsky Kyiv Polytechnic Institute in the world rankings of universities.