US 9,531,412 B2Granted

Systems and methods for a radio frequency transmitter with improved linearity and power out utilizing pre-distortion and a GaN (gallium nitride) power amplifier device

AssigneeAviat U.S., Inc.

InventorsJayesh Nath, Ying Shen, Frank Matsumoto, Youming Qin, David C. M. Pham

Life of this patent

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Abstract

Various embodiments provide for systems and methods for increased linear output power of a transmitter. An exemplary wireless communications system for transmitting an input signal comprises a predistorter module, a GaN power amplifier, a coupler, and an antenna. The predistorter module is configured to detect existing distortion by comparing the input signal to a feedback signal and generate a correction signal. The predistorter may adaptively adjust its operation to minimize the existing distortion due to GaN power amplifier nonlinear characteristics. The result is that the GaN power amplifier may send a power signal of improved linearity to the antenna. The coupler is configured to sample the amplified signal from the GaN power amplifier to generate the feedback signal. The antenna is configured to transmit the amplified signal.

Claims20

Dependent claims

A wireless communications system comprising:

a coupler configured to sample a first transmission signal at a transmission radio frequency to generate a feedback signal;
a first feedback downconverter configured to downconvert a first signal to an intermediate frequency to generate an intermediate frequency second signal, the first signal being based on the feedback signal from the transmission radio frequency;
a predistorter module configured to:
receive an intermediate frequency third signal, the intermediate frequency third signal being based on the intermediate frequency second signal;
compare the intermediate frequency third signal to an intermediate frequency input signal to detect existing distortion in the intermediate frequency third signal;
and
add inverse distortion to an output signal to generate a distorted output signal with added distortion, the inverse distortion added to the output signal being based on the existing distortion detected in the intermediate frequency third signal;
a second upconverter configured to upconvert an intermediate frequency fourth signal to generate a transmission radio frequency fifth signal, the intermediate frequency fourth signal being based on the distorted output signal to the transmission radio frequency;
a gallium nitride (GaN) power amplifier configured to amplify power of a transmission radio frequency sixth signal to generate a transmission radio frequency amplified signal, the GaN power amplifier adding amplifier distortion, wherein at least some of the added distortion from the predistorter module cancels at least some of the amplifier distortion, the transmission radio frequency sixth signal being based on the transmission radio frequency fifth signal;
and
an antenna configured to transmit a transmission radio frequency seventh signal, the seventh signal being based on the transmission radio frequency amplified signal.

8 more elements

A method comprising:

sampling a first transmission signal at a transmission radio frequency to generate a feedback signal;
downconverting a first signal to an intermediate frequency to generate an intermediate frequency second signal, the first signal being based on the feedback signal from the transmission radio frequency;
receiving, by a predistorter module, an intermediate frequency third signal, the intermediate frequency third signal being based on the intermediate frequency second signal;
comparing, by the predistorter module, the intermediate frequency third signal to an intermediate frequency input signal to detect existing distortion in the intermediate frequency third signal;
adding inverse distortion, by the predistorter module, to an output signal to generate a distorted output signal with added distortion, the inverse distortion added to the output signal being based on the existing distortion detected in the intermediate frequency third signal;
upconverting an intermediate frequency fourth signal to generate a transmission radio frequency fifth signal, the intermediate frequency fourth signal being based on the distorted output signal to the transmission radio frequency;
amplifying power, by a gallium nitride (GaN) power amplifier, of a transmission radio frequency sixth signal to generate a transmission radio frequency amplified signal, the GaN power amplifier adding amplifier distortion, wherein at least some of the added distortion from the predistorter module cancels at least some of the amplifier distortion, the transmission radio frequency sixth signal being based on the transmission radio frequency fifth signal;
and
transmitting, by an antenna, a transmission radio frequency seventh signal, the seventh signal being based on the transmission radio frequency amplified signal.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/704,468Filed 5 May 2015 · continuation
Priority: 11 Jan 2011
Published: US 2015/0236732 A120 Aug 2015
Granted: 27 Dec 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

H04B 1/0475
Circuits: with means for limiting noise, interference or distortion
H03F 1/3241
Modifications of amplifiers to reduce non-linear distortion: using predistortion circuits
H03F 1/3247
Using predistortion circuits: using feedback acting on predistortion circuits
H03F 1/345
Negative-feedback-circuit arrangements with or without positive feedback: using hybrid or directional couplers

Family

Application61/431,796Us provisional application · filed 11 Jan 2011
Application13/348,329Parent of this continuation · filed 11 Jan 2012
US 2015/0236732 A1Pre-grant publication · published 20 Aug 2015
US 9,065,397 B2Parent of this continuation
US 2012/0208477 A1Published application
US 9,531,412 B2This patent

From the US filing history. Foreign family members aren’t listed.