A dielectric resonator for a negative refractivity medium, which is coupled to a plurality of substrates, comprises at least one crystal unit, at least one first crystal cube and at least one second crystal cube. The crystal units are arrayed on the substrate. On an identical substrate, each crystal unit has a first spacing with respect to one adjacent crystal unit and a second spacing with respect to another adjacent crystal unit. The first spacing is vertical to the second spacing. Each crystal unit has one first crystal cube and one second crystal cube. A third spacing exists between the first and second crystal cubes. The first and second crystal cubes have a permittivity greater than 20. The present invention adopts the negative refractivity medium to achieve lower dielectric loss. Further, the present invention features isotropy and has low fabrication cost and high industrial utility.