Analog Beamformer Using Coupled Oscillators Instead of Phase Shifters
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Solution Overview
Problem
Conventional beamformers for array antennas suffer from signal loss and amplitude/phase errors due to phase shifters, especially at higher frequency bands like millimeter wave, which complicates the layout and increases estimation errors of reference symbol received power.
Innovation Solution
An analog beamformer architecture that eliminates phase shifters by using an intermediate-frequency amplifying circuit, multiple local oscillators, mixers, and a frequency locking circuit to generate radio-frequency signals with consistent frequency but different phases, forming a resonant network for frequency-and-phase-locking, thereby achieving phase adjustment without the drawbacks of phase shifters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase shifters are used in conventional beamformers, then phase adjustment can be achieved, but signal loss increases and amplitude/phase errors occur especially at millimeter wave frequencies
Solution Approach 1:
The patent removes phase shifters from the beamformer architecture entirely. Instead of using phase shifters to adjust signal phases, the invention extracts the phase adjustment function and implements it through multiple local oscillators that generate signals with different phases directly, eliminating the source of signal loss and amplitude/phase errors associated with phase shifters
Solution Approach 2:
The patent introduces local oscillators as intermediary components between the baseband signal and the antenna output. These local oscillators serve as mediators that provide the necessary phase differences through frequency mixing, avoiding the direct use of phase shifters that cause signal degradation
2Ease of operation
If phase shifters are implemented as integrated circuits with transmission lines and inductors, then phase adjustment is possible, but chip area increases and manufacturing cost rises
Solution Approach 1:
The patent replaces the physical phase shifter structure (transmission lines and inductors) with an electronic frequency mixing approach using local oscillators. This substitution eliminates the need for large physical components on the chip, significantly reducing the occupied area while maintaining phase adjustment functionality through electronic control of oscillator frequencies
3Adaptability or versatility
If multiple sets of mixers are added to the beamformer architecture, then frequency conversion capability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent merges the frequency conversion and phase adjustment functions into a unified architecture using multiple local oscillators. Instead of adding separate mixer sets for different functions, the invention combines these operations by having each local oscillator perform both frequency conversion and provide the necessary phase difference, thereby reducing overall device complexity
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 solution reduces signal transmission power loss, minimizes amplitude and phase errors, and decreases the estimation error of reference symbol received power, while also reducing the occupied circuit area, making it suitable for millimeter-wave beamforming integrated circuits.
Implementation Method 1
Power supplies or grounding ports of several local oscillators are connected together to generate frequency synchronization
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
AI summary
An analog beamformer used for array antenna and an operating method thereof are provided. The analog beamformer used for array antenna includes an intermediate-frequency amplifying circuit, multiple local oscillators, multiple mixers, multiple radio-frequency amplifying circuits, and a frequency locking circuit. 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 receives a baseband signal to provide an intermediate-frequency signal. Power supplies or grounding ports of different local oscillators are connected together to provide multiple local-oscillating signals with consistent frequency but different phases. The mixers individually receive the intermediate-frequency signal and one of the local-oscillating signals to provide multiple mixed signals. The radio-frequency amplifying circuits receive the mixed signals to provide multiple radio-frequency signals with consistent frequency but different phases to each antenna. The frequency locking circuit only locks a frequency of one of the local-oscillating signals.