Abstract:
A multiband matching circuit of the present invention includes an inductive element (42) having one end connected to an input terminal (P2), a first switch (SWL) having one end connected to the other end of the inductive element and the other end grounded, a capacitive element (41) having one end connected to the input terminal (P2), a second switch (SWH) having one end connected to the other end of the capacitive element and the other end grounded, a first-band matching circuit (10L) that is connected between the other end of the inductive element (42) and a first output terminal (P1L) and performs impedance matching in a first frequency band, and a second-band matching circuit (10H) that is connected between the other end of the capacitive element (41) and a second output terminal (P1H) and performs impedance matching in a second frequency band higher than the first frequency band.
Abstract:
A variable impedance matching circuit includes a series or parallel connection of a fixed inductive element and a first variable capacitive element and a second variable capacitive element connected in series with the serial or parallel connection. The susceptance of the circuit can be changed by changing the capacitances of the variable capacitive elements.
Abstract:
A variable resonator includes a first transmission line 101, a second transmission line 102 and a plurality of switch circuits 150. The electrical length of the first transmission line 101 is equal to the electrical length of the second transmission line 102. The characteristic impedance for the even mode of the first transmission line 101 is equal to the characteristic impedance for the even mode of the second transmission line 102. The characteristic impedance for the odd mode of the first transmission line 101 is equal to the characteristic impedance for the odd mode of the second transmission line 102. Each switch circuit 150 is connected to any of the first transmission line 101 and the second transmission line 102, and one of the switch circuits 150 is turned on.
Abstract:
A duplexer according to the present invention includes a first port, a second port and a third port for external input/output, a first path formed between the first port and the third port, a second path formed between the second port and the third port, a phase shifting part provided for each path, and a resonating part provided for each path. At least any of the resonating parts has a ring conductor having a length equal to one wavelength at a resonant frequency or an integral multiple thereof, a plurality of passive circuits, and a plurality of switches each of which is connected to a different part of the ring conductor at one end and to any of the passive circuits at the other end. A switch may simply be connected to a ground conductor instead of being connected to the passive circuit.
Abstract:
A multimode frontend circuit of the present invention comprises two transmission paths. Each of the transmission paths comprises two input/output lines, a first transmission line having one end connected to one of the input/output lines and the other end connected to the other input/output line, a second transmission line connected to the one of the input/output lines and the other end connected to the other input/output line, and one or more termination switch circuits. The termination switch circuit or circuits comprise a switch having one end connected to one of the first and second transmission lines and a termination circuit connected to the other end of the switch. Each of the transmission lines may comprise one or more short-circuiting switches. The short-circuiting switch or switches are capable of short-circuiting between the two transmission lines at positions at the same electrical length from one of the input/output lines.