A high frequency filter.

摘要

A high frequency filter for frequencies higher than the VHF band comprising a closed conductive housing (53), a pair of input and/or output means (54) like an antenna provided at both the extreme ends (53-5, 53-6) of said housing (53), a plurality of resonators (51-1 through 51-5, and 51a-1 through 51 a-5) arranged on a straight line between said antennas (54), each of said resonators having an elongated inner conductor (51a-1 through 51 a-5) with a circular cross section, and an elongated rectangular dielectric body (51-1 through 51-5) surrounding said inner conductor, one end of each of said resonators being fixed atthe single plane (53-1) of the housing (53) and the other end of each of said resonators being free standing. The length of said inner conductor and the dielectric body is substantially wavelength, and the distance (52-1 through 52-4) between two resonators is determined according tothe specified coupling coefficient for the desired characteristics of the filter. Due to the rectangular dielectric body (51-1 through 51-5), each resonator is stably mounted on the housing (53), and then, the stable characteristics of the filter is obtained. Thus, the use in a vibrated circumstance like a mobile communication is possible. That rectangular dielectric body (51-1 through 51-5) also provides the larger coupling coefficients between resonators, and then, the wideband filter can be obtained.