Active Phased Array Beam Squint Correction Using True Time Delay
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Solution Overview
Problem
Active phase array antenna systems experience beam squint issues when operating in wide instantaneous bandwidths, such as in millimeter wave 5G communication, where the beam steering direction shifts at frequencies other than the set frequency, leading to inaccurate beam steering.
Innovation Solution
The method involves adjusting the delay time of RF signals by employing true time delays in phase shifters and using a mixer to convert the operating frequency, effectively suppressing beam squint by adjusting the phase and frequency of the RF signals across multiple beamforming units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase shifters are used for beam steering in wide bandwidth applications, then beam steering capability is achieved, but beam squint occurs at frequencies other than the set frequency
Solution Approach 1:
The patent changes the delay parameter from constant (phase shifter) to frequency-proportional (true time delay) to resolve beam squint. By making the delay time proportional to the frequency offset from the center frequency, the system maintains accurate beam steering across wide bandwidths while preserving the beam steering capability of phase shifters.
2Measurement precision
If true time delay is arranged in each phase shifter to correct beam squint, then beam steering accuracy is improved, but system complexity increases
Solution Approach 1:
The patent segments the true time delay function across multiple beamforming units rather than implementing it in a single centralized component. Each beamforming unit incorporates its own true time delay element, which distributes the complexity and allows for modular implementation while achieving the beam squint correction effect across the entire array.
Solution Approach 2:
The patent integrates the true time delay function within the existing phase shifter structure, making the phase shifter multi-functional. Each phase shifter now performs both phase shifting and frequency-dependent delay compensation, reducing the need for separate components and thereby managing system complexity while improving beam steering accuracy.
3Adaptability or versatility
If mixer is employed to adjust operating frequency of true time delay, then frequency adaptability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a mixer as an intermediary component that translates the operating frequency of the true time delay element to match the RF signal frequency. The mixer acts as a frequency translation mediator, allowing the true time delay to operate at a different frequency while still providing the required delay function for the RF signal, thereby achieving frequency adaptability without requiring the true time delay element to directly handle all frequency variations.
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
This approach effectively corrects beam squint at frequencies other than the set frequency, ensuring accurate beam steering by adjusting the delay time and operating frequency of true time delays in phase array antenna systems, particularly in wide bandwidth applications like millimeter wave 5G communication.
Implementation Method 1
converting an operating frequency signal of the m/2 true time delays into an RF signal using a local signal and a mixer
Data Source
AI summary
A frequency conversion beam squint correction method of an active phase array antenna system including a plurality (m) of beamforming units configured of an antenna, a first amplifier, a phase shifter, a variable attenuator, and a second amplifier, the method includes the steps of: adjusting a delay time of an applied RF signal by arranging m/2 true time delays (TTDs) for every two adjacent beamforming units; and converting the frequency of the RF signal by mixing the RF signal transferred to each of the m/2 true time delays and a local oscillation signal using a mixer.