Dielectric filter, dielectric duplexer, and communication apparatus

摘要

There is disclosed a dielectric filter comprising: an attenuation band in proximity to a pass band; a threshold-frequency position of a determined maximum insertion loss being arranged close to a shoulder portion of a waveform exhibiting pass characteristics in which insertion losses increase in a region from the pass band to the attenuation band; temperature characteristics of a dielectric material being determined in such a manner that the shoulder portion moves toward the attenuation-band direction according to an increase and decrease in temperature.In the above dielectric filter, the deterioration of insertion-loss characteristics with respect to temperature changes is improved so that good characteristics are exhibited over a wide range of temperatures.