Phased array amplifier linearization
AssigneeAnalog Devices Global Unlimited Company
InventorsAhmed I. Khalil, Patrick Pratt
Life of this patent
Estimating the term…
Abstract
Apparatus and methods provide predistortion for a phased array. Radio frequency (RF) sample signals from phased array elements are provided along return paths and are combined by a hardware RF combiner. Phase shifters are adjusted such that the RF sample signals are phase-aligned when combined. Adaptive adjustment of predistortion for the amplifiers of the phased array can be based on a signal derived from the combined RF sample signals.
Claims22
An apparatus for radio frequency (RF) linearization of multiple amplifiers of a phased array, the apparatus comprising:
- a plurality of return paths configured to carry at least RF sample signals of a plurality of RF power amplifiers;
- a switch configured to electrically connect an antenna element to a transmit path in a first state and to electrically connect the antenna element to a receive path in a second state;
- an RF coupler electrically connected in series with the switch, the RF coupler configured to generate an RF sample signal of the RF sample signals, the RF coupler further configured to (i) selectively provide the RF sample signal between an RF power amplifier and the switch, and (ii) selectively provide the RF sample signal between the RF power amplifier and a return-side phase shifter;
- a hardware RF power combiner configured to combine the RF sample signals to generate a combined signal;
- a plurality of return-side phase shifters configured to adjust a phase shift of the RF sample signals such that the RF sample signals are phase aligned at the hardware RF power combiner;
- and
- a predistorter configured to predistort an input signal to generate a predistorted signal and configured to adapt predistortion coefficients for predistortion based at least partly on observations of a signal derived from the combined signal.
A method of linearization of multiple amplifiers of a phased array, the method comprising:
- sampling, with respective circuit elements coupled between respective radio frequency (RF) power amplifiers and antenna elements, signals generated by the RF power amplifiers to generate RF sample signals;
- providing the RF samples to hardware of respective receive paths arranged to process signals received from the antenna elements, wherein providing the RF samples comprises using hardware configured to (i) selectively provide an RF sample of the RF samples between an RF power amplifier of the RF power amplifiers and a switch, and (ii) selectively provide the RF sample between the RF power amplifier and a return-side phase shifter;
- phase shifting the RF sample signals such that the RF sample signals are phase aligned at a hardware RF power combiner;
- combining the RF sample signals the hardware RF power combiner to generate a combined signal;
- and
- predistorting an input signal with a predistorter to generate a predistorted signal, wherein predistortion coefficients are based at least partly on comparisons between portions of the input signal and corresponding portions of a signal derived from the combined signal.
Dependencies are inferred from the claim text.