A package structure is provided. The package structure includes an amplifier and a filter structure. The amplifier has an active surface. The filter structure is disposed over the amplifier, and communicates with the amplifier through a first signal path substantially vertical to the active surface of the amplifier.

A filter unit of a high-frequency module includes a plurality of SAW resonators connected in series between a first series connection terminal and a second series connection terminal, first shunt connection terminals, a second shunt connection terminal, and a plurality of SAW resonators. A connection line interconnecting the SAW resonators is connected to the first shunt connection terminal through one of the SAW resonators. The first shunt connection terminal is connected to a ground through an inductor. A matching circuit is connected between the second series connection terminal and a second external connection terminal. The matching circuit is inductively or capacitively coupled to the inductor.

A filter unit of a high-frequency module includes a plurality of SAW resonators connected in series between a first series connection terminal and a second series connection terminal, first shunt connection terminals, a second shunt connection terminal, and a plurality of SAW resonators. A connection line interconnecting the SAW resonators is connected to the first shunt connection terminal through one of the SAW resonators. The first shunt connection terminal is connected to a ground through an inductor. A matching circuit is connected between the second series connection terminal and a second external connection terminal. The matching circuit is inductively or capacitively coupled to the inductor.

A high-frequency module includes a connection line that interconnects a first SAW resonator and a second SAW resonator, and is connected to a second shunt connection terminal through a third SAW resonator. A connection line interconnecting a fourth SAW resonator and a second series connection terminal is connected to the second shunt connection terminal through a fifth SAW resonator. The second shunt connection terminal is connected to a ground through an inductor. A matching circuit is connected between a first series connection terminal and a first external connection terminal. The matching circuit is inductively or capacitively coupled to the inductor.

A high-frequency module includes a connection line that interconnects a first SAW resonator and a second SAW resonator, and is connected to a second shunt connection terminal through a third SAW resonator. A connection line interconnecting a fourth SAW resonator and a second series connection terminal is connected to the second shunt connection terminal through a fifth SAW resonator. The second shunt connection terminal is connected to a ground through an inductor. A matching circuit is connected between a first series connection terminal and a first external connection terminal. The matching circuit is inductively or capacitively coupled to the inductor.

Disclosed in one embodiment is filter circuitry having first and second paths extending between first and second nodes. The first path has a first inductor and a second inductor coupled in series between the first node and the second node, wherein the first inductor and the second inductor are positively coupled with one another, and a first common node is provided between the first inductor and the second inductor. First shunt acoustic resonators are coupled between the first common node and a fixed voltage node. The second path includes a third inductor and a fourth inductor coupled in series between the first node and the second node. The third inductor and the fourth inductor are negatively coupled with one another, and a second common node is provided between the third inductor and the fourth inductor. Second acoustic resonators are coupled between the second common node and a fixed voltage node.

Disclosed in one embodiment is filter circuitry having first and second paths extending between first and second nodes. The first path has a first inductor and a second inductor coupled in series between the first node and the second node, wherein the first inductor and the second inductor are positively coupled with one another, and a first common node is provided between the first inductor and the second inductor. First shunt acoustic resonators are coupled between the first common node and a fixed voltage node. The second path includes a third inductor and a fourth inductor coupled in series between the first node and the second node. The third inductor and the fourth inductor are negatively coupled with one another, and a second common node is provided between the third inductor and the fourth inductor. Second acoustic resonators are coupled between the second common node and a fixed voltage node.

An all-acoustic filter includes acoustic directional couplers and acoustic filters. In one embodiment, the all-acoustic filter includes two acoustic directional couplers, pair of matched acoustic filters corresponding to either transmit or receive frequency bands, and another acoustic filter corresponding to the other of transmit or receive frequency bands. An all-acoustic duplexer may be realized monolithically in a small form factor, may be tunable, may support multiple transmit or receive frequency bands, or may include schemes for antenna mismatch correction.

An acoustic wave filter device with two-stage acoustic wave filters is provided. Each of the two stages includes a respective acoustic wave filter element. A first acoustic wave filter element (100a) includes a first input electrode (150a), a first output electrode (174a), and a first counter electrode (120a). The first input electrode and the first output electrode are located on a top surface of piezoelectric layer (650), and the first counter electrode is located on a bottom surface of the piezoelectric layer. A second acoustic wave filter element (100b) includes a second input electrode (154b), a second output electrode (174b), and a second counter electrode (120b). The second input electrode and the second output electrode are located on the top surface of the piezoelectric layer, and the second counter electrode is located on a bottom surface of the piezoelectric layer. The two acoustic wave filter elements are connected in series through a common floating electrode (602).

An acoustic wave filter device with two-stage acoustic wave filters is provided. Each of the two stages includes a respective acoustic wave filter element. A first acoustic wave filter element (100a) includes a first input electrode (150a), a first output electrode (174a), and a first counter electrode (120a). The first input electrode and the first output electrode are located on a top surface of piezoelectric layer (650), and the first counter electrode is located on a bottom surface of the piezoelectric layer. A second acoustic wave filter element (100b) includes a second input electrode (154b), a second output electrode (174b), and a second counter electrode (120b). The second input electrode and the second output electrode are located on the top surface of the piezoelectric layer, and the second counter electrode is located on a bottom surface of the piezoelectric layer. The two acoustic wave filter elements are connected in series through a common floating electrode (602).