Active resonator system with tunable quality factor, frequency, and impedance
Active feedback is used with two electrodes of a four-electrode capacitive-gap transduced wine-glass disk resonator to enable boosting of an intrinsic resonator Q and to allow independent control of insertion loss across the two other electrodes. Two such Q-boosted resonators configured as parallel micromechanical filters may achieve a tiny 0.001% bandwidth passband centered around 61 MHz with only 2.7 dB of insertion loss, boosting the intrinsic resonator Q from 57,000, to an active Q of 670,000. The split capacitive coupling electrode design removes amplifier feedback from the signal path, allowing independent control of input-output coupling, Q, and frequency. Controllable resonator Q allows creation of narrow channel-select filters with insertion losses lower than otherwise achievable, and allows maximizing the dynamic range of a communication front-end without the need for a variable gain low noise amplifier.
1. A Q-boosted filter, comprising:
(a) a first Q-boosted resonator, said first Q-boosted resonator comprising:
(i) a resonant structure;
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes coupled to the resonant structure;
(iii) an amplifier, disposed between two or more feedback electrodes that is configured to form a feedback loop with the resonant structure;
(iv) wherein the gain and phase shift of the amplifier may be controlled to change an intrinsic Q of the resonant structure;
(b) a second Q-boosted resonator, said second Q-boosted resonator comprising:
(i) a resonant structure;
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes coupled to the resonant structure;
(iii) an amplifier, disposed between two or more feedback electrodes configured to form a feedback loop with the resonant structure;
(iv) wherein the gain and phase shift of the amplifier may be controlled to change an intrinsic Q of the resonant structure;
(v) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure; and
(c) a differential input signal comprising:
(i) a positive polarity connection to the input electrode of the first Q-boosted resonator;
(ii) a negative polarity connection to the input electrode of the second Q-boosted resonator;
(d) wherein the output electrode of the first Q-boosted resonator and the output electrode of the second Q-boosted resonator are connected together to provide a Q-boosted filter output.
2. The Q-boosted filter of claim 1 , wherein each said resonant structure is selected from a group of resonators consisting of: comb-driven resonators, piezo coupled resonators, ring resonators, contour mode ring resonators, wine-glass ring resonators, Lame mode resonators, bar resonators, flexural beam resonators, membrane resonators, comb-driven flexural-mode resonators, center-supported disk resonators, surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, film bulk acoustic resonator (FBAR) devices, lateral overmoded bulk acoustic-wave resonator (LOBAR) devices, piezo actuated resonators, internal dielectric actuated resonators, internally-transduced resonators having a capacitive couple formed from a semiconductor junction, and combinations of the foregoing.
3. The Q-boosted filter of claim 1 , wherein the differential input signal comprises:
(a) an input transformer, comprising:
(i) a primary winding;
(ii) a secondary winding having a grounded center tap;
(iii) the secondary winding having a positive polarity tap and a negative polarity tap; and
(b) wherein an input signal connected to the primary winding results in the differential input signal produced by the positive polarity tap and the negative polarity tap.
4. The Q-boosted filter of claim 1 , wherein the differential input signal is produced via a differential amplifier providing a positive polarity and a negative polarity output.
5. A Q-boosted filter, comprising:
(a) a first Q-boosted resonator, said first Q-boosted resonator comprising:
(i) a resonant structure;
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes electromechanically coupled to the resonant structure;
(iii) an amplifier, disposed between two or more feedback electrodes that is configured to form a feedback loop with the resonant structure;
(iv) wherein the gain and phase shift of the amplifier may be controlled to increase or decrease an intrinsic Q of the resonant structure; and
(b) one or more additional Q-boosted resonators, said Q-boosted resonators comprising:
(i) a resonant structure;
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes electromechanically coupled to the resonant structure;
(iii) an amplifier, disposed between two or more feedback electrodes configured to form a feedback loop with the resonant structure;
(iv) wherein the gain and phase shift of the amplifier may be controlled to increase or decrease an intrinsic Q of the resonant structure;
(v) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure; and
(c) one or more mechanical coupling beams connecting the Q-boosted resonator structure;
(d) wherein the output electrodes of all Q-boosted resonators are connected together to provide a Q-boosted filter output.
6. The Q-boosted filter of claim 5 , wherein each said resonant structure is selected from a group of resonators consisting of: comb-driven resonators, piezo coupled resonators, ring resonators, contour mode ring resonators, wine-glass ring resonators, Lame mode resonators, bar resonators, flexural beam resonators, membrane resonators, comb-driven flexural-mode resonators, center-supported disk resonators, surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, film bulk acoustic resonator (FBAR) devices, lateral overmoded bulk acoustic-wave resonator (LOBAR) devices, piezo actuated resonators, internal dielectric actuated resonators, internally-transduced resonators having a capacitive coupled formed from a semiconductor junction, and combinations of the foregoing.
7. The Q-boosted filter of claim 5 , wherein the differential input signal comprises:
(a) an input transformer, comprising:
(i) a primary winding; and
(ii) a secondary winding having a grounded center tap;
(iii) the secondary winding having a positive polarity tap and a negative polarity tap; and
(b) wherein an input signal connected to the primary winding results in the differential input signal produced by the positive polarity tap and the negative polarity tap.
8. The Q-boosted filter of claim 5 , wherein the differential input signal is produced via a differential amplifier providing a positive polarity output and a negative polarity output from a balanced input signal.
9. A Q-boosted filter, comprising:
(a) a first Q-boosted resonator, said first Q-boosted resonator comprising:
(i) a resonant structure;
(ii) an input electrode, an output electrode, a feedback input electrode, and a feedback output electrode, each of said electrodes coupled to the resonant structure;
(iii) wherein the resonant structure is configured to be biased by a tuning voltage relative to the input electrode, the output electrode, the feedback input electrode, and the feedback output electrode;
(iv) wherein the resonant structure has a resonant frequency that is changed by varying the tuning voltage; and
(v) an amplifier, disposed between the feedback input electrode and the feedback output electrode, that is configured to form a positive feedback loop with the resonant structure;
(vi) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure;
(b) a second Q-boosted resonator, said second Q-boosted resonator comprising:
(i) a resonant structure;
(ii) an input electrode, an output electrode, a feedback input electrode, and a feedback output electrode, each of said electrodes coupled to the resonant structure;
(iii) wherein the resonant structure is configured to be biased by a tuning voltage relative to the input electrode, the output electrode, the feedback input electrode, and the feedback output electrode;
(iv) wherein the resonant structure has a resonant frequency that is changed by varying the tuning voltage; and
(v) an amplifier, disposed between the feedback input electrode and the feedback output electrode, that is configured to form a positive feedback loop with the resonant structure;
(vi) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure; and
(c) an input transformer, comprising:
(i) a primary winding;
(ii) a secondary winding having a grounded center tap;
(iii) the secondary winding having a positive polarity connection to the input electrode of the first Q-boosted resonator;
(iv) the secondary winding having a negative polarity connection to the input electrode of the second Q-boosted resonator;
(d) wherein the output electrode of the first Q-boosted resonator and the output electrode of the second Q-boosted resonator are connected together to provide a Q-boosted filter output.
10. The Q-boosted filter of claim 9 , wherein an input signal connected to the primary winding results in the Q-boosted filter output.
11. The Q-boosted filter of claim 10 , wherein electrode coupling is selected from a group of couplings consisting of: capacitive and piezo-electric.
12. The Q-boosted filter of claim 10 , wherein each resonant structure is a wine-glass disk resonator.
13. The Q-boosted filter of claim 10 , wherein each resonant structure is supported above a substrate by one or more anchors.
14. The Q-boosted filter of claim 13 , wherein each resonant structure tuning voltage is transmitted through one or more of the anchors.
15. A Q-boosted resonator, comprising:
(a) a resonant structure;
(b) an input electrode, an output electrode, a feedback input electrode, and a feedback output electrode, each of said electrodes capacitively coupled to the resonant structure;
(c) wherein the resonant structure is configured to be biased by a tuning voltage relative to the input electrode, the output electrode, the feedback input electrode, and the feedback output electrode;
(d) wherein the resonant structure has a resonant frequency that is changed by varying the tuning voltage; and
(e) an amplifier, disposed between the feedback input electrode and the feedback output electrode, that is configured to form a positive feedback loop with the resonant structure;
(f) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure.
16. The Q-boosted resonator of claim 15 , wherein each amplifier comprises a transimpedance amplifier.
17. The Q-boosted resonator of claim 15 , wherein each resonant structure is selected from a group of resonators consisting of: comb-driven resonators, piezo coupled resonators, ring resonators, contour mode ring resonators, wine-glass ring resonators, Lame mode resonators, bar resonators, flexural beam resonators, membrane resonators, comb-driven flexural-mode resonators, center-supported disk resonators, surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, film bulk acoustic resonator (FBAR) devices, lateral overmoded bulk acoustic-wave resonator (LOBAR) devices, piezo actuated resonators, internal dielectric actuated resonators, internally-transduced resonators having a capacitive couple formed from a semiconductor junction, and combinations of the foregoing.
18. The Q-boosted resonator of claim 15 , wherein each resonant structure is supported above a substrate by one or more anchors.
19. The Q-boosted resonator of claim 18 , wherein each resonant structure tuning voltage is transmitted through one or more of the anchors.
20. A Q-boosted filter, comprising:
(a) a input transformer that couples a balanced input signal to two unbalanced Q-boosted resonators; and
(b) means for filtering, comprising:
(i) an input signal connected to the input transformer through the two unbalanced Q-boosted resonators; and
(ii) a filtered output signal formed by a connection of two output electrodes on the respective two unbalanced Q-boosted resonators;
(c) wherein each unbalanced Q-boosted resonator comprises:
(i) a resonant structure;
(ii) an input electrode, the output electrode, a feedback input electrode, and a feedback output electrode, each of said electrodes capacitively coupled to the resonant structure;
(iii) wherein the resonant structure is configured to be biased by a tuning voltage relative to the input electrode, the output electrode, the feedback input electrode, and the feedback output electrode; and
(iv) wherein the resonant structure has a resonant frequency that is changed by varying the tuning voltage; and
(v) an amplifier, disposed between the feedback input electrode and the feedback output electrode, that is configured to form a positive feedback loop with the resonant structure;
(vi) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure.
21. A method of Q-boosted filtering, comprising:
(a) providing an input signal;
(b) splitting the input signal into two signals 180° out of phase;
(c) passing each of the 180° out of phase signals through a respective Q-boosted resonator;
(d) combining each output of the Q-boosted resonators into a Q-boosted filter output; and
(e) controlling a resonant frequency of each Q-boosted resonator;
(f) wherein a substantially flat pass band is formed between the resonance frequencies of the two Q-boosted resonators.
22. A method of Q-boosted filtering, comprising:
(a) providing an input signal;
(b) splitting the input signal into two signals 180° out of phase;
(c) passing each of the 180° out of phase signals through a respective Q-boosted resonator;
(d) combining each output of the Q-boosted resonators into a Q-boosted filter output;
(e) controlling a resonant frequency of each Q-boosted resonator;
(f) wherein a substantially flat pass band is formed between the resonance frequencies of the two Q-boosted resonators;
(g) wherein each Q-boosted resonator comprises:
(i) a resonant structure; and
(ii) an input electrode, the output electrode, a feedback input electrode, and a feedback output electrode, each of said electrodes capacitively coupled to the resonant structure.
23. The method of Q-boosted filtering of claim 22 , wherein controlling the resonant frequency for one of the Q-boosted resonators comprises applying a bias voltage between the resonant structure of the Q-boosted resonator and the input electrode, the output electrode, the feedback input electrode, and the feedback output electrode, each of said electrodes capacitively coupled to the resonant structure.
24. A Q-boosted filter, comprising:
(a) a first Q-boosted resonator, said first Q-boosted resonator comprising:
(i) a resonant structure; and
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes coupled to the resonant structure;
(b) a second Q-boosted resonator, said second Q-boosted resonator comprising:
(i) a resonant structure; and
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes coupled to the resonant structure;
(c) an amplifier, disposed between feedback electrodes of both Q-boosted resonators, configured to form feedback loops with both resonant structures simultaneously;
wherein the gain and phase shift of the amplifier may be controlled to change the Qs of the resonant structures; and
(d) a differential input signal comprising:
(i) a positive polarity connection to the input electrode of the first Q-boosted resonator;
(ii) a negative polarity connection to the input electrode of the second Q-boosted resonator;
(e) wherein the output electrode of the first Q-boosted resonator and the output electrode of the second Q-boosted resonator are connected together to provide a Q-boosted filter output.
25. The Q-boosted filter of claim 24 , wherein each said resonant structure is selected from a group of resonators consisting of: comb-driven resonators, piezo coupled resonators, ring resonators, contour mode ring resonators, wine-glass ring resonators, Lame mode resonators, bar resonators, flexural beam resonators, membrane resonators, comb-driven flexural-mode resonators, center-supported disk resonators, surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, film bulk acoustic resonator (FBAR) devices, lateral overmoded bulk acoustic-wave resonator (LOBAR) devices, piezo actuated resonators, internal dielectric actuated resonators, internally-transduced resonators having a capacitive couple formed from a semiconductor junction, and combinations of the foregoing.
26. The Q-boosted filter of claim 24 , wherein the differential input signal comprises:
(a) an input transformer, comprising:
(i) a primary winding; and
(ii) a secondary winding having a grounded center tap;
(iii) the secondary winding having a positive polarity tap and a negative polarity tap;
(b) wherein an input signal connected to the primary winding results in the differential input signal produced by the positive polarity tap and the negative polarity tap.
27. The Q-boosted filter of claim 24 , wherein the differential input signal is produced via a differential amplifier providing a positive polarity and a negative polarity output from an input signal.
28. A Q-boosted filter, comprising:
(a) a first Q-boosted resonator, said first Q-boosted resonator comprising:
(i) a resonant structure; and
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes electromechanically coupled to the resonant structure;
(b) one or more additional Q-boosted resonators, said Q-boosted resonators comprising:
(i) a resonant structure; and
(ii) an input electrode, an output electrode, and one or more feedback electrodes, each of said electrodes electromechanically coupled to the resonant structure;
(c) an amplifier, disposed between feedback electrodes of both Q-boosted resonators that is configured to form feedback loops with both resonant structures simultaneously;
(i) wherein the gain and phase shift of the amplifier may be controlled to change the Qs of the resonant structures; and
(d) one or more mechanical coupling beams connecting the Q-boosted resonator structure;
(e) wherein the output electrodes of all Q-boosted resonators are connected together to provide a Q-boosted filter output.
29. The Q-boosted filter of claim 28 , wherein each said resonant structure is selected from a group of resonators consisting of: comb-driven resonators, piezo coupled resonators, ring resonators, contour mode ring resonators, wine-glass ring resonators, Lame mode resonators, bar resonators, flexural beam resonators, membrane resonators, comb-driven flexural-mode resonators, center-supported disk resonators, surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, film bulk acoustic resonator (FBAR) devices, lateral overmoded bulk acoustic-wave resonator (LOBAR) devices, piezo actuated resonators, internal dielectric actuated resonators, internally-transduced resonators having a capacitive couple formed from a semiconductor junction, and combinations of the foregoing.
30. The Q-boosted filter of claim 28 , wherein the differential input signal comprises:
(a) an input transformer, comprising:
(i) a primary winding; and
(ii) a secondary winding having a grounded center tap;
(iii) the secondary winding having a positive polarity tap and a negative polarity tap;
(b) wherein an input signal connected to the primary winding results in the differential input signal produced by the positive polarity tap and the negative polarity tap.
31. The Q-boosted filter of claim 28 , wherein the differential input signal is produced via a differential amplifier providing a positive polarity output and a negative polarity output from a balanced input signal.
32. A Q-boosted resonator, comprising:
(a) a resonant structure;
(b) at least four electrodes coupled to the resonant structure;
(c) wherein the resonant structure is configured to be biased by a tuning voltage relative to the electrode that is an input, the electrode that is an output, the electrode that is a feedback input, and the electrode that is a feedback output; and
(d) wherein the resonant structure has a resonant frequency that is changed by varying the tuning voltage; and
(e) an amplifier, disposed between the feedback input electrode and the feedback output electrode, that is configured to form a positive feedback loop with the resonant structure;
(f) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure; and
(g) wherein each resonant structure is selected from a group of resonators consisting of: comb-driven resonators, piezo coupled resonators, ring resonators, contour mode ring resonators, wine-glass ring resonators, Lame mode resonators, bar resonators, flexural beam resonators, membrane resonators, comb-driven flexural-mode resonators, center-supported disk resonators, surface acoustic wave (SAW) devices, bulk acoustic wave (BAW) devices, film bulk acoustic resonator (FBAR) devices, lateral overmoded bulk acoustic-wave resonator (LOBAR) devices, piezo actuated resonators, internal dielectric actuated resonators, internally-transduced resonators having a capacitive couple formed from a semiconductor junction, and combinations of the foregoing.
33. A Q-boosted resonator, comprising:
(a) a resonant structure;
(b) at least four electrodes coupled to the resonant structure;
(c) wherein the resonant structure is configured to be biased by a tuning voltage relative to the electrode that is an input, the electrode that is an output, the electrode that is a feedback input, and the electrode that is a feedback output; and
(d) wherein the resonant structure has a resonant frequency that is changed by varying the tuning voltage; and
(e) an amplifier, disposed between the feedback input electrode and the feedback output electrode, that is configured to form a positive feedback loop with the resonant structure;
(f) wherein the positive feedback loop is configured to boost an intrinsic Q of the resonant structure; and
(g) wherein each resonant structure is supported above a substrate by one or more anchors.
34. The Q-boosted resonator of claim 33 , wherein each resonant structure tuning voltage is transmitted through one or more of the anchors.