Electro-acoustic filter

1. A device comprising:

a plurality of electrode actuated acoustic resonators coupled to form complementary paths to operate as a filter, each acoustic resonator having an electrical input and an electrical output; and

a compensation impedance coupled to at least one of the paths,

wherein at least one of the paths includes a 180° phase shift.

2. The device of claim 1 , wherein the compensation impedance is coupled to the at least one path to reduce an acoustic resonator static capacitance effect in the filter.

3. The device of claim 1 , wherein the compensation impedance is configured to reduce the acoustic resonator static capacitance effect on filter bandwidth.

4. A communication device comprising:

at least one transceiver;

at least one antenna; and

at least one device according to claim 1 .

5. The device of claim 1 wherein the compensation impedance comprises a capacitor coupled in parallel with a resonator in one path.

6. The device of claim 1 wherein the compensation impedance comprises a negative capacitance coupled between one path and ground.

7. The device of claim 1 wherein the compensation impedance comprises a capacitor coupled in parallel with a resonator in one path and a negative capacitance coupled between one path and ground.

8. The device of claim 1 wherein the compensation impedance comprises a compensation impedance coupled in series with one path.

9. The device of claim 1 , wherein the acoustic resonators are Bulk Acoustic Wave (BAW) resonators having a Q of approximately 2000 or higher.

10. The device of claim 1 , wherein the acoustic resonators are Surface Acoustic Wave (SAW) resonators having a Q of approximately 2000 or higher.

11. The device of claim 1 , wherein the acoustic resonators have acoustic coupling coefficients, and wherein the compensation impedance is configured to offset decreases in the acoustic coupling coefficients of the acoustic resonators.

12. A device comprising:

a plurality of electrode actuated acoustic resonators coupled to form complementary paths to operate as a filter, each acoustic resonator having an electrical input and an electrical output; and

a compensation impedance coupled to at least one of the paths,

wherein the complementary paths include straight paths and phase shifted paths, and wherein the compensation impedance has a value determined to offset a static capacitance difference that is a function of the sum of static capacitances in the straight paths as compared to the sum of the static capacitances in the phase shifted paths.

13. A communication device comprising:

at least one transceiver;

at least one antenna; and

at least one device according to claim 12 .

14. A device comprising:

a differential input port;

a differential output port;

a plurality of electrode actuated acoustic resonators coupled to form a filter including transverse complementary paths between the differential input port and the differential output port to operate as a bandpass filter, each acoustic resonator being part of a path; and

a compensation impedance coupled to at least one of the paths to reduce an acoustic resonator static capacitance effect in the filter,

wherein the complementary paths include straight paths and criss-cross paths, and wherein the compensation impedance has a value determined to offset a static capacitance difference that is a function of the sum of static capacitances in the straight paths as compared to the sum of the static capacitances in the criss-cross paths.

15. A communication device comprising:

at least one transceiver;

at least one antenna; and

at least one device according to claim 14 .

16. A device comprising:

a differential input port;

a differential output port;

a plurality of electrode actuated acoustic resonators coupled to form a filter including transverse complementary paths between the differential input port and the differential output port to operate as a bandpass filter, each acoustic resonator being part of a path; and

a compensation impedance coupled to at least one of the paths to reduce an acoustic resonator static capacitance effect in the filter,

wherein the compensation impedance comprises a capacitor coupled in parallel with a resonator in one path.

17. The device of claim 16 , wherein the compensation impedance includes an inductance element coupled between electrodes of the differential input port.

18. The device of claim 16 , wherein the acoustic resonators are Bulk Acoustic Wave (BAW) resonators.

19. The device of claim 16 , wherein the acoustic resonators are Surface Acoustic Wave (SAW) resonators having a Q of approximately 2000 or higher.

20. A communication device comprising:

at least one transceiver;

at least one antenna; and

at least one device according to claim 16 .

21. A device comprising:

differential input port;

a differential output port;

a plurality of electrode actuated acoustic resonators coupled to form a filter including transverse complementary paths between the differential input port and the differential output port to operate as a bandpass filter, each acoustic resonator being part of a path; and

a compensation impedance coupled to at least one of the paths to reduce an acoustic resonator static capacitance effect in the filter,

wherein the compensation impedance comprises a negative capacitance coupled between one path and a complementary criss-cross path.

22. The device of claim 21 wherein the compensation impedance further comprises a capacitor coupled in parallel with a resonator in one path.

23. A communication device comprising:

at least one transceiver;

at least one antenna; and

at least one device according to claim 21 .

24. A method comprising:

determining a first sum of static capacitances in a first set of acoustic resonator paths in a filter;

determining a second sum of static capacitances in a second set of acoustic resonator paths in the filter, wherein the second set of paths are complementary to the first set of paths; and

adding a compensation impedance to one of the paths as a function of the first and second sums.