Pidhurska T. Higher-order mode dual-band dielectric resonator filters

The thesis is devoted to design of dual-band filters on dielectric resonators with higher-order modes, which includes the development of both mathematical models and new structural designs that provide the necessary electrical parameters with minimum number of coupling elements. The objective of the study is to provide a technique for the construction as well as structural design of dual-band filters on dielectric resonators with higher-order modes. In the thesis a new technique for the dual-band filter design has been proposed, which is different in that it requires to ensure the same dependence of the corresponding coupling coefficients on the design parameters for both operating modes of dielectric resonator that allows to realize a bandpass filter with two bandwidths. An analytical model for the mutual coupling coefficient between the rectangular dielectric resonators operating in the higher-order "quadrupole" mode has been derived based on the field expansion in evanescent waves of rectangular waveguide. A mathematical model of dual-band multiresonator filter has been developed, which in contrast to existing ones takes into account the coefficients' dependencies in two bands at the same time thus allowing the synthesis of such filters on the basis of the proposed technique.