Radio frequency module

1. A radio frequency module comprising:

a transmission terminal to which a transmission signal is input;

a transmission filter connected to the transmission terminal and including a ground terminal through which the transmission signal passes;

a common terminal from which the transmission signal having passed through the transmission filter is output, and to which a reception signal is input;

a reception filter which is connected to the common terminal, and through which the reception signal passes;

a reception terminal from which the reception signal having passed through the reception filter is output;

a branch point to which the common terminal, the transmission filter, and the reception filter are connected;

a transmission path connecting the transmission terminal and the branch point;

a reception path connecting the reception terminal and the branch point;

a common path connecting the common terminal and the branch point;

a matching circuit connected to the common path; and

an inductor circuit including one end connected to the ground terminal and another end connected to a ground, the inductor circuit adjusting characteristics of the transmission filter; wherein

the inductor circuit includes:

a first inductor that defines a propagation path through electromagnetic coupling to at least one of the transmission path, the common path, the matching circuit, and the reception path; and

a second inductor that is positioned so as not to be electromagnetically coupled to the transmission path, the common path, the matching circuit, or the reception path.

2. The radio frequency module according to claim 1 , further comprising:

a module substrate including mounting electrodes to which the transmission terminal, the reception terminal, the common terminal, and the ground terminal are connected; wherein

the matching circuit, the inductor circuit, and a ground electrode are electrically connected to the ground;

the transmission filter and the reception filter are mounted on the module substrate; and

the ground electrode is located between the first inductor and the second inductor.

3. The radio frequency module according to claim 2 , wherein the module substrate includes a multilayer substrate including a plurality of insulator layers that are laminated, and the first inductor and the second inductor are located inside the multilayer substrate so as to sandwich the ground electrode.

4. The radio frequency module according to claim 2 , wherein one of the first inductor and the second inductor is defined by a chip surface mounted component and is mounted on the module substrate, and another one of the first inductor and the second inductor is defined by a wiring electrode that is disposed in the module substrate.

5. The radio frequency module according to claim 1 , wherein the first inductor and the second inductor are positioned so as not to be overlapped with each other when viewed in a plan view.

6. The radio frequency module according to claim 1 , wherein the transmission filter and the reception filter are integral with each other to define a duplexer, and the second inductor is located inside the duplexer.

7. The radio frequency module according to claim 6 , wherein the duplexer has a wafer level package structure.

8. The radio frequency module according to claim 6 , wherein

the duplexer includes a device substrate, a support layer provided on the device substrate, and a cover layer provided on support layer such that a space is provided between the cover layer and the device substrate, the space being surrounded by the support layer; and

the transmission filter and the reception filter are provided on the device substrate in the space.

9. The radio frequency module according to claim 8 , wherein the support layer is made of one of a photosensitive epoxy resin and a polyimide resin.

10. The radio frequency module according to claim 8 , wherein the cover layer is made of one of a photosensitive epoxy resin and a polyimide resin.

11. The radio frequency module according to claim 8 , wherein the device substrate is a piezoelectric body, and the at least one of the transmission filter and the reception filter is defined by a surface acoustic wave filter.

12. The radio frequency module according to claim 11 , wherein both of the transmission filter and the reception filter are defined by surface acoustic wave filters.

13. The radio frequency module according to claim 12 , wherein the transmission filter includes a plurality of series arm resonators arranged in series in the transmission path and a plurality of parallel arm resonators respectively connected between connection junctions of the plurality of series arm resonators and the ground terminal.

14. The radio frequency module according to claim 12 , wherein the reception filter includes a phase shifter resonator, and a longitudinally-coupled resonator defining a band pass filter connected in series to the phase shifter resonator.

15. The radio frequency module according to claim 1 , wherein the matching circuit includes an inductor.

16. The radio frequency module according to claim 2 , wherein the matching circuit includes an inductor defined by a chip surface mounted component that is mounted on the module substrate.

17. The radio frequency module according to claim 1 , wherein the reception filter is a balanced filter.

18. The radio frequency module according to claim 1 , wherein

the matching circuit is defined by a first chip surface mounted component;

the first inductor is defined by a second chip surface mounted component; and

the first and second chip surface mounted components are mounted adjacent to each other on the module substrate.