System and method for dynamic impedance tuning to minimize return loss

1. A system for tuning an impedance at a node, comprising:

a first component associated with a first impedance when the first component is operating and a second impedance when the first component is not operating;

a second component coupled to the first component at a node, the second component associated with a third impedance when the second component is operating and a fourth impedance when the second component is not operating; and

an impedance tuning circuit coupled to the second component at the node and operable to tune an impedance at the node based at least in part upon a plurality of the first impedance, the second impedance, the third impedance, and the fourth impedance.

2. The system of claim 1 , wherein the first component comprises one of:

an amplifier;

an attenuator;

a mixer; and

a filter.

3. The system of claim 1 , wherein the second component is not operating when the first component is operating and the first component is not operating when the second component is operating.

4. The system of claim 1 , wherein the second impedance and the fourth impedance each comprises a parasitic impedance.

5. The system of claim 1 , wherein the impedance tuning circuit comprises a plurality of switchable capacitors.

6. The system of claim 1 , wherein the impedance tuning circuit comprises a plurality of transistors, each transistor associated with a capacitance.

7. The system of claim 1 , wherein the impedance at the node comprises the sum of at least the first impedance, the second impedance, and the fourth impedance when the first component is operating and the second component is not operating.

8. The system of claim 1 , wherein the impedance at the node comprises the sum of at least the second impedance, the third impedance, and the fourth impedance when the second component is operating and the first component is not operating.

9. The system of claim 1 , further comprising a plurality of additional components, each additional component coupled to the node and contributing to the impedance at the node.

10. The system of claim 1 , wherein the impedance tuning circuit tunes the impedance at the node over a broadband range of frequencies.

11. The system of claim 1 , wherein the impedance tuning circuit contributes a variable impedance in order to tune the impedance at the node.

12. The system of claim 1 , wherein the first component, the second component, and the impedance tuning circuit are formed on an integrated circuit.

13. The system of claim 12 , further comprising:

a component external to the integrated circuit and associated with an output impedance; and

an impedance matching circuit coupled to the external component and the integrated circuit at the node, the impedance matching circuit operable to transform the output impedance of the external component to the impedance at the node.

14. The system of claim 12 , further comprising an impedance matching circuit coupled to the node, wherein the impedance matching circuit operates with the impedance tuning circuit to minimize the return loss of the system across a broadband range of frequencies.

15. The system of claim 12 , wherein the impedance tuning circuit tunes the impedance at the node such that a fixed impedance matching network external to the integrated circuit may be used to minimize the return loss of the system across a broadband range of frequencies.

16. A system for minimizing return loss, comprising:

a plurality of components coupled to each other at a node, wherein each component is associated with a first impedance when the component is operating and a second impedance when the component is not operating;

an impedance tuning circuit coupled to the plurality of components at the node and operable to tune an impedance at the node based upon at least some of the first impedances of the plurality of components and further based upon at least some of the second impedances of the plurality of components; and

an impedance matching circuit coupled to the node and operable to minimize a return loss of the system across a broadband range of frequencies based at least in part upon the impedance at the node.

17. The system of claim 16 , wherein the plurality of components and the impedance tuning circuit are formed on an integrated circuit.

18. The system of claim 17 , wherein the impedance matching circuit is external to the integrated circuit and the system further comprising a component external to the integrated circuit and associated with an output impedance.

19. The system of claim 18 , wherein the impedance matching circuit transforms the output impedance of the external component to the impedance at the node in order to minimize the return loss of the system.

20. The system of claim 16 , wherein the impedance tuning circuit comprises a plurality of switchable capacitors.

21. The system of claim 16 , wherein the impedance tuning circuit comprises a plurality of transistors, each transistor associated with a capacitance.

22. The system of claim 16 , wherein the impedance tuning circuit tunes the impedance at the node over a broadband range of frequencies.

23. The system of claim 16 , wherein the impedance tuning circuit contributes a variable impedance in order to tune the impedance at the node.

24. A system, comprising:

a plurality of components coupled to each other at a node, wherein each component is associated with a first impedance when the component is operating and a second impedance when the component is not operating; and

means for tuning the impedance at the node over a broadband range of frequencies based upon at least some of the first impedances of the plurality of components and further based upon at least some of the second impedances of the plurality of components.

25. The system of claim 24 , further comprising means for minimizing a return loss of the system across a broadband range of frequencies based at least in part upon the impedance at the node.