CALIBRATION FOR A TUNABLE RF FILTER STRUCTURE

摘要

Embodiments of radio frequency (RF) front-end circuitry are disclosed where the RF front-end circuitry includes a tunable RF filter structure and a calibration circuit. The tunable RF filter structure includes (at least) a pair of weakly coupled resonators and defines a transfer function with a passband. The calibration circuit is configured to shape the passband so that the passband defines a center frequency. Additionally, the calibration circuit is configured to detect a phase difference at the target center frequency between the pair of weakly coupled resonators and adjust the phase difference of the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency. In this manner, the calibration circuit calibrates the tunable RF filter structure to correct for errors in the center frequency of the passband due to component manufacturing variations.

主权项

1. A radio frequency (RF) front-end circuitry, comprising:
a tunable RF filter structure comprising a pair of weakly coupled resonators, wherein the tunable RF filter structure is tunable to define a transfer function with a passband; a calibration circuit configured to: shape the passband so that the passband defines a center frequency;
detect a phase difference between the pair of weakly coupled resonators at a target center frequency; andadjust the phase difference between the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency.