ACTIVE RESONATOR SYSTEM WITH TUNABLE QUALITY FACTOR, FREQUENCY, AND IMPEDANCE

摘要

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.

主权项

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.