Adaptive antenna module

1. An adaptive antenna module comprising:

a signal path;

a series resonant antenna that is electrically connected to the signal path;

a detector electrically connected to the signal path for detecting impedance matching of the adaptive antenna module, the detector configured to generate a signal representing a detected phase of a radio frequency (RF) signal propagating in the signal path;

a tuning circuit comprising two variable impedance elements, the variable impedance elements comprising a variable series impedance element that is electrically connected in series within the signal path and a variable shunt impedance element that is electrically connected in series within a first parallel path electrically connecting the signal path with ground, each variable impedance element having an impedance value responsive to an impedance setting associated with the variable impedance element;

wherein the tuning circuit comprises logic configured to:

compare the signal representing the detected phase with phase values stored in a lookup table, each phase value stored in the lookup table corresponding to an entry stored in the lookup table; and

set the impedance setting associated with each of the variable impedance elements in response to an entry in the lookup table corresponding to a phase value matching the detected phase;

wherein the tuning circuit is constrained by the entries stored in the lookup table to operate over a restricted range of impedances defined by the possible impedance values of the variable impedance elements.

2. The adaptive antenna module of claim 1 , wherein the variable series impedance element and the variable shunt impedance element are impedance elements with variable capacitances.

3. The adaptive antenna module of claim 1 , further comprising a first inductance element electrically connecting the signal path with ground.

4. The adaptive antenna module of claim 1 , further comprising a capacitance element electrically connecting the antenna with ground.

5. The adaptive antenna module of claim 1 , further comprising a second inductance element electrically connecting the signal path with ground.

6. The adaptive antenna module of claim 1 , further comprising

a third inductance element electrically connected in series within the signal path, and

a first switch electrically connected in series within the signal path and in parallel to the third inductance element.

7. The adaptive antenna module of claim 1 , further comprising a fourth inductance element electrically connected in series within the signal path.

8. The adaptive antenna module of claim 7 , further comprising a double-tuning circuit having

a second parallel path electrically connecting the signal path with ground;

a parallel resonant circuit having a fifth inductance element electrically connected within the second parallel path and a variable capacitance element electrically connected in parallel to the fourth inductance element; and

a second switch electrically connected in series within the second parallel path between the signal path and the parallel resonant circuit.

9. The adaptive antenna module of claim 1 , wherein the antenna comprises an antenna selected from the group consisting of a PIFA, a PILA, and a rod antenna.

10. The adaptive antenna module of claim 1 , further comprising a fourth inductance element electrically connected in series within the signal path and wherein the detector comprises a phase detector that is electrically connected in parallel to the fourth inductance element.

11. The adaptive antenna module of claim 1 , wherein the adaptive antenna module is usable in GSM-, CDMA-, or WCDMA-systems.

12. An adaptive antenna module comprising:

a signal path;

an antenna node electrically connected to the signal path and configured to be coupled to an antenna;

a variable series impedance element electrically connected in series within the signal path;

a variable shunt impedance element electrically connected between the signal path and a ground node;

a first inductance element electrically connected between the signal path and the ground node;

a second inductance element electrically connected between the signal path and the ground node;

a third inductance element electrically connected in series within the signal path;

a first switch electrically connected in parallel with the third inductance element;

a fourth inductance element electrically connected in series within the signal path;

a parallel resonant circuit electrically connected between the signal path and the ground node, the parallel resonant circuit comprising a fifth inductance element electrically connected in parallel with a variable capacitance element; and

a second switch electrically connected between the signal path and the parallel resonant circuit.

13. The adaptive antenna module of claim 12 , further comprising a detector electrically connected in parallel with the fourth inductance element.

14. The adaptive antenna module of claim 12 , wherein:

the fourth inductance element is coupled between the second switch and the third inductance element;

the third inductance element is coupled between the fourth inductance element and the variable series impedance element;

the variable series impedance element is coupled between the third inductance element and the antenna node;

the second inductance element is coupled to the signal path at a location between the third inductance element and the variable series impedance element; and

the first inductance element is coupled to the signal path at a location between the variable series impedance element and the antenna node.

15. The adaptive antenna module of claim 12 , further comprising an antenna electrically connected to the antenna node.

16. The adaptive antenna module of claim 15 ,

wherein the antenna is series resonant;

wherein a tuning circuit is formed by the variable series impedance element and the variable shunt impedance element; and

wherein the tuning circuit operates over a restricted range of impedances that is defined by the possible values of the variable impedance elements.