Active Phase Switchable Array for Simultaneous Vital Sign Detection
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Solution Overview
Problem
Conventional passive phase arrays require more active control elements, leading to increased power loss, complexity, and cost, while lacking the ability to efficiently detect vital signs of multiple subjects simultaneously.
Innovation Solution
An active phase switchable array with antenna elements that operate in self-injection-locked and mutual-injection-locked states, utilizing a bias circuit to control the free-running frequency of injection-locked oscillators and produce phase differences between output signals for beamforming and vital sign detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a passive phase array uses more active control elements to control signals, then the beamforming capability is improved, but the power loss increases
Solution Approach 1:
The patent employs self-injection-locked oscillators at each antenna element that automatically lock to a common frequency without requiring external control signals. This self-service mechanism eliminates the need for complex active control elements and power splitters, thereby maintaining beamforming capability while significantly reducing power loss in the control network.
Solution Approach 2:
The system divides the phase control function into independent segments at each antenna element through the use of self-injection-locked oscillators. Each oscillator independently maintains frequency synchronization through mutual coupling, replacing the centralized control architecture with distributed autonomous control, thus reducing power consumption in the control path.
2Adaptability or versatility
If a passive phase array uses more active control elements, then the beamforming capability is improved, but the control complexity increases
Solution Approach 1:
The self-injection-locked oscillators automatically synchronize to a common frequency through mutual coupling between adjacent elements, eliminating the need for complex external control circuits. This self-organizing behavior reduces control complexity while preserving beamforming functionality through natural frequency locking and phase synchronization.
Solution Approach 2:
The patent combines the frequency control and phase control functions into a single mutual-injection-locking mechanism. By merging these functions, the system achieves beamforming capability without requiring separate control circuits for frequency and phase, thereby simplifying the overall control architecture.
3Adaptability or versatility
If a passive phase array uses more active control elements, then the beamforming capability is improved, but the cost increases
Solution Approach 1:
The self-injection-locked oscillators eliminate the need for expensive active control elements such as voltage-controlled oscillators and phase shifters. By using passive mutual coupling between simple oscillator circuits, the system achieves beamforming capability with significantly reduced component count and lower manufacturing cost.
Solution Approach 2:
The patent replaces expensive, complex active control components with simpler, cheaper self-injection-locked oscillator circuits. These simpler oscillators, when mutually coupled, provide the necessary beamforming functionality at a lower cost, making the system more economically viable.
4Measurement precision
If the antenna element operates in self-injection-locked state, then the sensitivity to subject's vibration is improved for detecting vital sign, but the beamforming capability may be affected
Solution Approach 1:
The patent merges the self-injection-locked state (which provides vibration sensitivity) with the mutual-injection-locked state (which provides beamforming capability). By coupling both mechanisms, the system simultaneously achieves vital sign detection sensitivity and directional beamforming, resolving the apparent contradiction between these two functions.
Solution Approach 2:
The self-injection-locked oscillator serves multiple functions: it provides frequency stability for beamforming through mutual coupling, while simultaneously maintaining sensitivity to frequency modulations caused by subject vibrations. This multi-functionality allows a single mechanism to fulfill both beamforming and vital sign detection requirements.
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
Enables direction-adjustable beamforming and simultaneous detection of vital signs from multiple subjects with reduced power loss and complexity, enhancing communication and search capabilities.
Implementation Method 1
the antenna is configured to radiate the output signal to a subject, wherein a reflected signal reflected from the subject is received by the antenna and transmitted to the ILO through the power coupling network to allow the ILO to operate in a self-injection-locked state
Implementation Method 2
the power coupling network of one of the antenna elements is coupled to the power coupling network of the other antenna element, and the output signal from the ILO of the other antenna element is transmitted to the ILO of the antenna element through the power coupling networks to allow the ILO to operate in a mutual-injection-locked state
Implementation Method 3
The bias circuit is configured to output a plurality of modulation voltages, wherein the modulation voltages are respectively transmitted to the ILO of each of the antenna elements to control a free-running frequency of each of the ILOs
Implementation Method 4
produce the phase difference between the output signals of the antenna elements by the mutual-injection-locked mechanisms of the antenna elements to allow the active phase switchable array possess the capability of the beamforming
Data Source
AI summary
An active phase switchable array includes a plurality of antenna elements and a bias circuit. Each of the radar elements includes an antenna, a power coupling network and an injection-locked oscillator (ILO), and each of the antenna elements is coupled with each other through the power coupling networks for operating the ILO of each of the antenna elements in self- and mutual-injection-locked states. The antenna elements in self-injection-locked state are utilized to detect the vital signs of subjects, and the antenna elements in mutual-injection-locked state are utilized to produce phase difference between the radiating signals of the antenna elements for forming a beam. As a result, the active phase switchable array can simultaneously detect the vital signs of multiple subjects.