BAND-PASS FILTER MODULE AND MODULE SUBSTRATE

摘要

A bandpass filter module includes a mounting board and a BPF chip mounted on a surface thereof. The BPF chip includes three or more resonators; a first-stage resonator located closest to an input terminal, a final-stage resonator located closest to an output terminal, and a middle-stage resonator connected between the first-stage and the final-stage resonators and located in a chip middle zone. The mounting board includes an area overlapping with the chip middle zone, viewed in plan, defining a ground-free space in which no ground electrode is disposed. The ground-free space is formed at least from the surface of the mounting board to a depth position at which a topmost internal wiring layer is located. The middle-stage resonator is prevented from being coupled to ground electrodes on the mounting board and from a lower Q-value and increased insertion loss.