The present invention relates to a resonator structure composed of two dielectric pieces. On the upper surface of a first piece (1) is provided a groove (7) extending across the entire surface and coated with an electrically conductive agent, said coating being at least in one end connected with an electrically conductive coating serving as a ground plane, so that the groove (7) forms a transmission line resonator. On the upper surface of the second piece (2) is provided a conductive strip (9) running in the middle of the surface, said strip forming a transmission line resonator. The pieces (1,2) are placed with the upper surfaces thereof against each other and attached to each other so that the groove (7) and the strip (9) are against one another in parallel, whereby the groove and the strip together form a resonator.