Dielectric filter, composite dielectric filter, dielectric duplexer, dielectric diplexer, and communication apparatus incorporating the same

A composite dielectric filter comprising:

• at least first and second dielectric filters,
• said first dielectric filter comprising a group of resonators which are mutually coupled to form a series of said resonators extending in a defined direction,
• said second dielectric filter comprising a group of resonators which are mutually coupled to form a series of said resonators extending in said defined direction,
• each said resonator including a dielectric core disposed in a cavity and being associated with a pair of coupling loops, the first coupling loop along said defined direction having a first coupling portion, the second coupling loop along said defined direction having a second coupling portion, each of said coupling portions being disposed in said cavity for coupling to a predetermined resonance mode of the dielectric resonator, wherein:
• a plurality of resonators in said first dielectric filter are adjacent to a respective plurality of resonators in said second dielectric filter,
• said first coupling portion in said resonator in said first filter is substantially perpendicular to said first coupling portion in said resonator in said second filter, and
• said second coupling portion in said resonator in said first filter is substantially perpendicular to said second coupling portion in said resonator in said second filter.

A dielectric filter comprising:

• at least first and second groups of dielectric resonators,
• said first group of resonators being mutually coupled to form a series of said resonators extending in a defined direction,
• said second group of resonators being mutually coupled to form a series of said resonators extending in said defined direction,
• each said resonator including a dielectric core disposed in a cavity and being associated with a pair of coupling loops, the first coupling loop along said defined direction having a first coupling portion, the second coupling loop along said defined direction having a second coupling portion, each of said coupling portions being disposed in said cavity for coupling to a predetermined resonance mode of the dielectric resonator, wherein:
• a resonator in said first group of resonators is adjacent to a resonator in said second group of resonators,
• said first coupling portion in said resonator in said first group is substantially perpendicular to said first coupling portion in said resonator in said second group, and
• said second coupling portion in said resonator in said first group is substantially perpendicular to said second coupling portion in said resonator in said second group, and wherein:
• said first and second groups of dielectric resonators are arranged so that a signal is received at a signal input portion connected to said first group, then flows through said first group in said defined direction, then flows through said second group in a direction opposite to said defined direction, and then reaches a signal output portion connected to said second group of dielectric resonators.