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

1. Field of the Invention A dielectric filter, a composite dielectric filter, a dielectric duplexer, a dielectric diplexer, and a communication apparatus, in which isolation between adjacent dielectric filters can be obtained, and deterioration of filter characteristics can thereby be prevented. A plurality of dielectric resonators formed by disposing dielectric cores in cavities, and coupling loops for coupling to predetermined resonance modes of the dielectric resonators, are combined to form a dielectric filter. The dielectric resonators and the coupling loops are arranged in such a manner that when the dielectric resonators of the dielectric filters are close to each other, the directions of the coupling portions of the adjacent coupling loops are substantially vertical to each other.