High frequency filter, filter device, and electronic apparatus incorporating the same

Abstract

The invention provides a high frequency filter which can facilitate filter-characteristic adjustments and miniaturization and can obtain an excellent broadband characteristic. In addition, the invention provides a filter device using the high frequency filter, and an electronic apparatus incorporating the same. In this filter, a ground electrode is arranged on one of the main surfaces of a dielectric substrate. On the other main surface thereof there are arranged two or more microstrip lines, and one end of each microstrip line is grounded via a through-hole to form a high frequency filter. The microstrip lines and the shared through-hole constitute microstrip line resonators, which are coupled via the inductance of the through-hole. With this arrangement, there is no need for an additional coupling element. Thus, the size of the high frequency filter can be reduced. Furthermore, since a large coupling coefficient can be obtained, the high frequency filter can have a broadband characteristic.

Dependencies are inferred from the claim text.