The invention provides a three-mode
dielectric resonator which comprises a
dielectric block, the
dielectric block is provided with a pair of first resonant blind holes, a pair of second resonant blind holes and a third resonant
blind hole, the first resonant blind holes are arranged along a first
diagonal direction of the dielectric block and used for forming a first resonant mode, and the second resonant blind holes are arranged along a second
diagonal direction of the dielectric block and used for forming a third resonant mode. The pair of second
resonance blind holes are arranged along a second
diagonal direction of the dielectric block and are used for forming a second
resonance mode, the third
resonance blind holes are used for forming a third resonance mode, and the first diagonal direction and the second diagonal direction intersect with each other. The invention also provides a dielectric
waveguide filter and a dielectric
waveguide duplexer using the
resonator unit. When the
resonator unit is used for designing a dielectric
waveguide filter, a three-mode waveguide structure with independently adjustable resonant
modes is realized, multiple resonant
modes are realized under the same volume, the overall Q value benefit is achieved, and the resonator unit has the advantages of
miniaturization and high Q value benefit.