Analog Beamformer Using Locked Oscillators Instead of Phase Shifters
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Solution Overview
Problem
Existing beamformers for array antennas suffer from significant signal loss, amplitude errors, and phase errors due to the use of phase shifters, especially at higher frequencies like millimeter waves, which also complicate feeder path routing and increase chip area and cost.
Innovation Solution
An analog beamformer architecture that eliminates phase shifters by using local oscillators with frequency-and-phase-locking networks, where power and grounding ports are connected to form resonant networks, enabling phase adjustment without the drawbacks of phase shifters, thus minimizing power loss and errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If phase shifters are used in the beamformer architecture, then phase adjustment capability is provided, but signal loss increases significantly at higher frequencies
Solution Approach 1:
The patent removes phase shifters from the beamformer architecture entirely, extracting the problematic component that causes signal loss. Instead of using phase shifters to adjust phase, the invention uses a different approach: multiple local oscillators with controlled frequency offsets that naturally produce the required phase differences through frequency tuning, eliminating the need for phase shifting operations that cause energy loss at millimeter wave frequencies.
Solution Approach 2:
The patent changes the operating parameters of local oscillators by applying different frequency offset controls to each oscillator. This parameter change (frequency offset) directly produces the desired phase differences in the mixed signals without requiring phase shifters. By controlling the frequency of local oscillators rather than shifting phase after mixing, the system achieves phase adjustment capability without the associated signal loss.
2Ease of operation
If phase shifters are used in the beamformer architecture, then phase control is achieved, but amplitude errors are introduced
Solution Approach 1:
The patent extracts and removes phase shifters from the system, eliminating the source of amplitude errors that accompany phase control in conventional architectures. The replacement method uses frequency-offset local oscillators combined with mixing, which provides phase control through frequency manipulation rather than phase shifting, thereby avoiding the amplitude errors that plague phase shifter-based systems.
Solution Approach 2:
The patent substitutes the mechanical/electrical phase shifting mechanism with a frequency-based control mechanism. Instead of using phase shifters that physically or electrically adjust phase (which introduce amplitude errors), the system uses local oscillators with controlled frequency offsets that produce phase differences through the mixing process, replacing the problematic phase control mechanism with a cleaner frequency control approach.
3Ease of operation
If phase shifters are used in the beamformer architecture, then phase adjustment is possible, but phase errors increase
Solution Approach 1:
The patent removes phase shifters from the architecture, eliminating the component that introduces phase errors. The phase adjustment function is replaced by controlling the frequency offsets of multiple local oscillators, which generate phase differences through frequency tuning rather than phase shifting. This extraction of the error-prone phase shifter component and replacement with frequency-controlled oscillators directly addresses the phase error problem.
Solution Approach 2:
The patent changes the control parameter from phase shifting to frequency offset control. By controlling the frequency of local oscillators through offset adjustments rather than using phase shifters, the system achieves phase adjustment with higher precision. The frequency offset parameter provides a more accurate and stable means of controlling phase relationships compared to phase shifter mechanisms, reducing phase errors in the final beamformed output.
4Ease of manufacture
If phase shifters are implemented as integrated circuits, then the beamformer can be integrated, but chip area is occupied by transmission lines and inductors
Solution Approach 1:
The patent extracts and removes phase shifters from the integrated circuit architecture, eliminating the need for large transmission lines and inductors that would otherwise be required on the chip. By replacing phase shifters with frequency-offset local oscillators and mixers, the design reduces the area occupied by passive components while maintaining integrated circuit manufacturability. The active mixing approach requires smaller footprint components compared to the passive transmission line and inductor structures needed for phase shifting.
5Reliability
If multiple sets of mixers are added to the beamformer architecture, then frequency conversion is improved, but device complexity increases
Solution Approach 1:
The patent combines the frequency conversion and phase adjustment functions into a unified approach using multiple local oscillators with frequency offsets. Instead of adding separate mixer sets for different functions, the invention merges frequency conversion with phase control by having each local oscillator perform both roles simultaneously through its frequency-offset signal. This merging reduces the total number of mixers needed while maintaining reliable frequency conversion across all antenna channels.
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 reduces signal transmission power loss, avoids amplitude and phase errors, and minimizes chip area, facilitating efficient millimeter-wave beamforming with improved feeder path layout.
Implementation Method 1
multiple local oscillators... provide multiple local-oscillating signals with consistent frequency but different phases
Implementation Method 2
The mixers individually receive the intermediate-frequency signal and one of the local oscillating signals, and the mixers provide multiple mixed signals
Implementation Method 3
The frequency locking circuit is only coupled to one of the local oscillators and then lock in the frequency of the coupled local oscillator
Implementation Method 4
Several radio-frequency amplifying circuits receive the mixed signals to provide multiple radio-frequency signals with consistent frequency but different phases to different antennas
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
An analog beamformer used for array antenna (100, 200, 300, 400, 500, 600) and an operating method thereof are provided. The analog beamformer used for array antenna (100, 200, 300, 400, 500, 600) includes an intermediate-frequency amplifying circuit (VGAIF), multiple local oscillators (OSCi-OSCn, OSCx), multiple mixers (Mixer1-Mixern, Mixerx), multiple radio-frequency amplifying circuits (VGA1-VGAn, VGAx), and a frequency locking circuit (130). The analog beamformer uses a master-oscillator and multiple slave-oscillators which embed a resonant network of frequency-and-phase-locking. The intermediate-frequency amplifying circuit (VGAIF) receives a baseband signal (SBB) to provide an intermediate-frequency signal (SIF). Power supplies or grounding ports of different local oscillators (OSC1-OSCn, OSCx) are connected together to provide multiple local-oscillating signals (CLKL1-CLKLn) with consistent frequency but different phases. The mixers (Mixer1-Mixern, Mixerx) individually receive the intermediate-frequency signal (SIF) and one of the local-oscillating signals (CLKL1-CLKLn) to provide multiple mixed signals (Smx1-Smxn). The radio-frequency amplifying circuits (VGA1-VGAn, VGAx) receive the mixed signals (Smx1-Smxn) to provide multiple radio-frequency signals (SRF1-SRFn) with consistent frequency but different phases to each antenna (ANT1-ANTn). The frequency locking circuit (130) only locks a frequency of one of the local-oscillating signals (CLKL1-CLKLn).