| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable filter capable of achieving steep attenuation characteristics while suppressing the increase of insertion loss. SOLUTION: A first variable resonator (10), a second variable resonator (20) and a third variable resonator (30), consisting of series circuits composed of capacitive elements (12, 22, 32) and inductors (11, 21, 31), respectively, at least one of each set of the capacitive element and the inductor being a variable element, as basic unit circuits, are provided between a first input/output terminal (1a) and a second input/output terminal (1b). The first variable resonator is connected in series between the two input/output terminals, the second variable resonator is connected to a point between the first input/output terminal and the first variable resonator at one end of the second variable resonator and is grounded at the other end, and the third variable resonator is connected to a point between the second input/output terminal and the first variable resonator at one end of the third variable resonator and is grounded at the other end. COPYRIGHT: (C)2011,JPO&INPIT |
