FILTER DEVICE WITH PHASE COMPENSATION AND ELECTRONIC DEVICE INCLUDING THE SAME

摘要

PROBLEM TO BE SOLVED: To improve the isolation characteristics of an antenna duplexer.SOLUTION: A filter 400 includes: a main filter circuit 410 having a first phase characteristic between an input and an output; and a phase shift circuit 420 connected in parallel to the main filter circuit. The phase shift circuit 420 includes a first capacitor element 422, a second capacitor element 428, and a pair of elastic wave elements 424 and 426 serially connected between the first capacitor element and the second capacitor element. The pair of elastic wave elements include a pair of separate inclined finger IDT electrodes in one elastic wave route where elastic waves propagate through the elastic wave elements. The phase shift circuit has a second phase characteristic opposite to the first phase characteristic in an attenuation band at least partially corresponding to the rejection band of the main filter circuit.SELECTED DRAWING: Figure 3B