Power Amplifier Interference Cancellation Loop for Antenna Arrays
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Solution Overview
Problem
Existing radio frequency systems face challenges in managing interference between antennas in antenna arrays due to limited isolation, leading to degradation in linearity and efficiency of power amplifiers, especially in high-frequency and massive MIMO systems, where isolators are impractical and costly.
Innovation Solution
Implementing an interference cancellation loop with a radio frequency coupler, amplifier, and phase shifter to generate a cancellation signal that suppresses interference at the output of the power amplifier, without the need for isolators, and optionally applying the cancellation signal at the input or between stages of the power amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If isolators are used to reduce interference between antennas, then interference suppression is improved, but device complexity and cost increase
Solution Approach 1:
The patent captures the harmful interfering signal using a coupler and converts it into a useful cancellation signal by processing it through amplification and phase shifting, then subtracting it from the original signal to eliminate interference without requiring isolators
Solution Approach 2:
The patent implements a feedback mechanism where the interfering signal is continuously monitored, processed, and fed back as a cancellation signal to counteract the interference in real-time, achieving dynamic interference suppression
2Object-affected harmful factors
If isolators are used to reduce interference between antennas, then interference suppression is improved, but cost increases
Solution Approach 1:
The patent replaces expensive isolators with a cost-effective circuit implementation using standard components (coupler, amplifier, phase shifter, subtractor) that achieves the same interference suppression function at lower cost
Solution Approach 2:
The patent transforms the harmful interfering signal into a useful cancellation signal through processing, eliminating the need for expensive isolator hardware
3Volume of moving object
If antenna arrays with limited isolation are used, then system compactness is improved, but linearity and efficiency of power amplifiers deteriorate
Solution Approach 1:
The patent converts the harmful effect of closely-spaced antennas causing interference into a beneficial solution by capturing and processing the interference signal to create a cancellation signal, enabling compact antenna arrays to maintain high linearity and efficiency
Solution Approach 2:
The patent uses feedback to continuously monitor and cancel interference signals, allowing compact antenna arrays to operate with high linearity and efficiency despite close spacing
4Reliability
If interference cancellation loop is added, then linearity is improved, but device complexity increases
Solution Approach 1:
The patent segments the interference cancellation function into distinct modular components (coupler, amplifier, phase shifter, subtractor), making the system easier to design, implement, and maintain while achieving improved linearity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces interference and improves linearity, achieving desired EVM and OOB emissions performance without the inefficiencies and cost of isolators, while allowing for wide beam scanning angles and compact designs.
Implementation Method 1
The radio frequency coupler is configured to generate an interfering power signal
Implementation Method 2
The interference cancellation loop includes an amplifier and is configured to receive the interfering power signal and to provide a cancellation signal
Implementation Method 3
The interference cancellation loop can further include a phase shifter. The interference cancellation loop can be configured to generate the cancellation signal by at least amplifying and phase shifting the interfering power signal
Implementation Method 4
The interference cancellation loop is configured to receive the interfering power signal and to provide a cancellation signal to the transmit signal path to thereby suppress interference at the output of the power amplifier
Data Source
AI summary
Aspects of this disclosure relate to a cancelling interference at an output of a power amplifier. An interference sensing circuit in a signal path between the power amplifier and an antenna can generate an interfering power signal. An interference cancellation loop can receive the interfering power signal and provide a cancellation signal to a transmit signal path that includes the power amplifier to thereby suppress interference at the output of the power amplifier. In certain embodiments, the interference cancellation loop includes an amplifier and a phase shifter. Related systems and methods are disclosed.