Dielectric resonator device, dielectric filter, dielectric duplexer, and communication apparatus

A dielectric resonator device comprising:

• a substantially rectangular dielectric plate having upper and lower opposed surfaces;
• a respective electrode provided on each of the upper and lower opposed surfaces of the dielectric plate;
• and
• at least two mutually-opposing openings formed in the respective electrodes,
• wherein respective portions between the mutually-opposing openings define main resonance regions which function as respective resonators, and
• wherein at least one of the mutually-opposing openings defining the main resonance regions of the resonators is a resonator for externally inputting/outputting a signal and being substantially rectangular, and at least one edge of the at least one of the at least two mutually-opposing openings is located at one edge of the dielectric plate.