Integrated directional coupler within an RF matching network

1. An integrated directional coupler comprising:

a tuned matching network having an inductive element to carry a first radio frequency (RF) signal, the inductive element including a first segment and a second segment; and

a coupled conductive element to carry a second RF signal, the coupled conductive element being configured to be electromagnetically coupled to the inductive element such that the second RF signal is representative of the first RF signal, the coupled conductive element including a third segment and a fourth segment that are inductively coupled respectively to the first and second segment of the inductive element, wherein the coupling is achieved through vertical coupling between the first and third segments and lateral coupling between the second and fourth segments.

2. The integrated directional coupler of claim 1 wherein the tuned matching network is an output match circuit of a power amplifier.

3. The integrated directional coupler of claim 1 wherein a first width of said inductive element is different than a second width of said coupled conductive element.

4. The integrated direction coupler of claim 1 wherein at least part of said inductive element is disposed in a multi-layer substrate and wherein at least part of said coupled conductive element is disposed in the multi-layer substrate.

5. The integrated directional coupler of claim 4 wherein the inductive element comprises an upper trace in said multi-layer substrate and the coupled conductive element comprises a lower trace in said multi-layer substrate.

6. The integrated directional coupler of claim 4 wherein said inductive element includes upper and lower traces and wherein said coupled conductive element is between said upper and lower traces.

7. The integrated directional coupler of claim 4 wherein said coupled conductive element includes more than one segment that is electromagnetically coupled to said inductive element.

8. The integrated directional coupler of claim 3 further comprising a shield, said shield operable to prevent undesirable coupling into said coupled conductive element.

9. The integrated directional coupler of claim 3 wherein part of said tuned matching network resides on a CMOS die that is coupled to said multi-layer substrate.

10. The integrated directional coupler of claim 3 wherein part of said tuned matching network resides on a die that is flip chip mounted to said multi-layer substrate.

11. An integrated directional coupler comprising:

an inductive element within a power amplifier carrying a first radio frequency (RF) signal;

a coupled conductive element carrying a second RF signal;

wherein the coupled conductive element is configured to be electromagnetically coupled to the inductive element of the power amplifier such that the second RF signal is representative of the first RF signal;

wherein said coupled conductive element includes a first segment and a second segment that are inductively coupled respectively to a third and fourth segment of the inductive element of the power amplifier, wherein the coupling is achieved through vertical coupling between the first and third segments and lateral coupling between the second and fourth segments; and

wherein said inductive element of the power amplifier has a first characteristic impedance that is different than a second characteristic impedance of said coupled conductive element.

12. The integrated directional coupler of claim 11 wherein the first characteristic impedance of said inductive element of the power amplifier is different than 50-ohm.

13. The integrated directional coupler of claim 11 wherein at least part of said inductive element is disposed in a multi-layer substrate and wherein at least part of said coupled conductive element is disposed in the multi-layer substrate.

14. The integrated directional coupler of claim 13 wherein the inductive element of the power amplifier comprises an upper trace in said multi-layer substrate and the coupled conductive element comprises a lower trace in said multi-layer substrate.

15. The integrated directional coupler of claim 11 wherein a first wire width of said inductive element of the power amplifier is different than a second wire width of said coupled conductive element.

16. The integrated directional coupler of claim 11 wherein the inductive element of the power amplifier is part of a tuned matching network within the power amplifier.

17. The integrated directional coupler of claim 16 wherein the tuned matching network of the power amplifier is an output match.

18. A method of making a directional coupler comprising:

forming at least a portion of an inductive element of a power amplifier in a multi-layer substrate, the at least a portion of the inductive element including a first segment and a second segment, the inductive element being part of a tuned matching network within the power amplifier; and

forming a conductive element in the multi-layer substrate, the conductive element configured to be electromagnetically coupled to the inductive element such that the conductive element carries a second radio frequency (RF) signal that is representative of a first RF signal within the inductive element, the conductive element including a third segment inductively coupled to the first segment of the at least a portion of the inductive element and a fourth segment inductively coupled to the second segment of the at least a portion of the inductive element, wherein the coupling is achieved through vertical coupling between the first and third segments and lateral coupling between the second and fourth segments.