LC FILTER CIRCUIT, LAMINATE TYPE LC FILTER, MULTIPLEXER, AND RADIO COMMUNICATION DEVICE

摘要

PROBLEM TO BE SOLVED: To design an attenuation electrode without varying a center frequency range and to provide an LC filter, multiplexer, and radio communication device which are small-sized. SOLUTION: A laminate type LC filter 1 has inductors L1 and L3 of a low- pass filter circuit and an inductor L of a trap circuit arranged in different layers in the stacking direction of insulator sheets 2 to 8. Via holes 11a and 11b, and 12a and 12b for the inductors are connected successively in the stacking direction of the insulator sheets 2 to 8 to form columnar inductors. The via holes 11a and 11b for the inductor are connected to a conductor pattern 9 for a coil electrically in series to constitute the inductor L1. The via holes 12a and 12b for the inductor are connected to a conductor pattern 10 for a coil electrically in series to constitute the inductor L3. A via hole 15 for an inductor constitutes a columnar inductor L2 alone.