Phase Rotator Amplitude Control Unit for Low Power Beamforming
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Solution Overview
Problem
Existing digital beamforming techniques face challenges with high power consumption, heat dissipation, and complexity due to the need for high-speed ADCs and complex data interfaces, while analog beamforming has limited accuracy in phase and gain adjustments, especially at higher frequencies.
Innovation Solution
A Phase Rotator and Amplitude Control Unit (PRAU) with switched transconductance branches controlled by digital phase and amplitude control parameters, enabling precise phase rotation and amplitude control with low power consumption, using a configuration of Phase Rotator and Amplitude control Circuits (PRAC) with open drain topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital beamforming is used to create multiple beams, then the ability to apply multiple sets of weight vectors simultaneously is improved, but power consumption increases due to high-speed ADCs
Solution Approach 1:
The patent segments the beamforming process into analog phase/gain adjustment at the antenna elements followed by digital processing. This allows multiple beams to be formed in analog domain using phase rotators and variable gain amplifiers, reducing the burden on ADCs and subsequent digital processing power consumption
Solution Approach 2:
The patent introduces analog beamforming circuitry (phase rotators, variable gain amplifiers, combiners) as an intermediary between the antenna elements and the ADCs. This intermediary layer performs preliminary signal processing in the analog domain, reducing the data rate and processing requirements for the digital portion of the system
2Adaptability or versatility
If digital beamforming is used to create multiple beams, then multiple simultaneous beams can be formed, but device complexity increases due to high-speed FPGAs and complex data interfaces
Solution Approach 1:
The patent divides the beamforming architecture into separate analog and digital segments. The analog segment handles multiple beam formation through parallel phase rotators and combiners, while the digital segment processes the combined output. This segmentation reduces the complexity of data interfaces between chips or dies
Solution Approach 2:
The patent combines multiple analog beamformed signals into a single combined analog signal before ADC conversion. This merging approach reduces the number of separate high-speed data interfaces needed, as multiple beams are processed through a unified analog path before digital conversion
3Use of energy by moving object
If analog beamforming is used to adjust phase and gain, then power consumption is reduced, but manufacturing precision deteriorates due to limited accuracy in variable gain amplifiers and phase rotators
Solution Approach 1:
The patent incorporates feedback mechanisms in the analog beamforming circuitry, particularly in the variable gain amplifiers and phase rotators. This feedback enables automatic calibration and compensation for manufacturing variations, improving the precision of phase and gain adjustments while maintaining low power consumption
Solution Approach 2:
The patent uses digitally controllable analog components where parameters such as phase shift and gain can be precisely adjusted through digital control words. This allows the analog circuitry to achieve high precision by changing operational parameters rather than relying solely on physical manufacturing tolerances
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 PRAU achieves high accuracy and low power consumption, simplifying the control interface and facilitating larger arrays by digital control of switched transconductance branches, addressing the limitations of both digital and analog beamforming methods.
Implementation Method 1
A Phase Rotator and Amplitude Control Unit (PRAU) with switched transconductance branches controlled by digital phase and amplitude control parameters
Data Source
Figure 1
Figure 2(a)~2(c)
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AI summary
A Phase Rotator and Amplitude control Unit, PRAU (500), for performing phase rotation and amplitude control of an input signal and generating an output signal with an individual phase shift is disclosed. The PRAU (500) comprises a plurality N1 of Phase Rotator and Amplitude control Circuits, PRAC. Each PRAC comprises an input port comprising in-phase and quadrature-phase inputs to receive the input signal; an output port comprising in-phase and quadrature-phase outputs, control inputs to receive phase and amplitude control parameters. The phase and amplitude control parameters comprise sign control signals and positive amplitude coefficient signals, and each positive amplitude coefficient signal has N1 digital bits. Each PRAC further comprises a plurality of switched transconductance branches, and each switched transconductance branch comprises one transconductance transistor connected in series with two switching transistors.