In this paper a novel design of an E-plane bandstop waveguide filter with a double-sided printed-circuit insert is presented. Split-ring resonators are used as the resonating elements to obtain the bandstop response. The amplitude response of the waveguide resonator with a single resonating element on the insert is analyzed for various dimensions and positions of the split-ring resonator. The coupling between two resonators on the insert, in terms of their mutual distance, is considered as a next step to the filter design. Various positions of the resonators are considered, including the case with the resonators on the different sides of the insert, which is of interest for the proposed filter design. Finally, a third-order bandstop filter with a double-sided printed-circuit insert, operating in the X-frequency band, is introduced. The filter response is analyzed for various distances between the resonators and for various positions of the resonator printed on the other side of the insert. Proposed filter design is simple, providing for the accurate fabrication, miniaturization and possibility to relatively easy obtain multi-band response, using resonators with different resonant frequencies on the different sides of the insert
