Dielectric filter, dielectric duplexer, and communication apparatus using the same

摘要

A dielectric filter and a dielectric duplexer have simple structures, in each of which the resonance frequency of a TE mode is controlled in such a manner that no TE-mode spurious response occurs in a band requiring attenuation. Specifically, the distance between the central position of each of inner-conductor-formed holes (2a, 2b) and a widthwise line (C) of a dielectric block (1) is set to be two times or more than the distance between the central position of each of the holes (2a, 2b) and a lengthwise line (H) thereof. With this arrangement, the resonance frequency of a spurious mode such as a TE101 mode is shifted to the low-frequency side to deviate the resonance frequency of the spurious mode from a band requiring attenuation, for example, from a band near the second-order harmonic of a TEM mode, as a mode to be used. In addition, a communication apparatus is formed by using one of the filter and the duplexer described above. <IMAGE>