Dynamic Sensor Array Using Shape Memory Alloy
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Solution Overview
Problem
Existing UWB radar sensor arrays experience performance degradation due to fixed sensor distances that do not match the half wavelength of the transmitted signal, particularly within the 77 GHz to 81 GHz frequency range specified by FCC regulations.
Innovation Solution
A sensor array with shape memory alloy (SMA) connected to its sensors, allowing for controllable deformation to adjust the distance between sensors to match varying frequencies and wavelengths, thereby maintaining optimal performance across the desired frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are fixed at a certain distance to receive RF signal at a specific frequency, then the array performance is optimized for that frequency, but performance degrades when operating at other frequencies within the 77 GHz to 81 GHz range
Solution Approach 1:
The patent applies the dynamics principle by making the sensor array configuration changeable through shape memory alloys (SMAs). The SMAs enable the sensors to be dynamically repositioned along the array structure, allowing the inter-sensor distance to be adjusted according to the operating frequency. This transforms a static array into a dynamic one that can adapt its geometry to maintain optimal performance across different frequencies within the 77 GHz to 81 GHz range.
Solution Approach 2:
The patent implements parameter changes by utilizing the phase transition properties of shape memory alloys. When the SMA undergoes phase change (from austenite to martensite or vice versa), it changes its physical dimensions, which in turn changes the distance between sensors. This parameter change in the SMA's length directly controls the sensor spacing, enabling the array to adjust its configuration for different operating frequencies while maintaining reliable performance.
2Ease of manufacture
If the distance between sensors is fixed, then the manufacturing and assembly process is simplified, but the array cannot maintain optimal performance across varying frequencies and wavelengths
Solution Approach 1:
The patent applies the self-service principle through the shape memory alloy's ability to automatically change its length in response to temperature or electrical stimulus. The SMA elements can be actuated by applying voltage or heating, causing them to expand or contract and thereby automatically adjusting the sensor positions without requiring complex external actuation mechanisms. This self-adjusting capability maintains performance consistency across frequencies while keeping the overall system relatively simple.
Solution Approach 2:
The patent utilizes phase transitions of shape memory alloys as the core mechanism for adjusting sensor distances. The SMA materials undergo reversible phase changes (austenite-martensite transformation) that result in significant length changes. By controlling the phase transition through temperature or electrical fields, the system can switch between different sensor configurations optimized for different frequencies, maintaining reliable performance without complicating the manufacturing process.
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 SMA-enabled sensor array maintains high performance by dynamically adjusting sensor distances to match the wavelength of received RF signals, reducing performance degradation and ensuring effective operation within the 77 GHz to 81 GHz bandwidth.
Implementation Method 1
The SMA is controllably deformable to vary the distance between the at least two of the plurality of sensors
Data Source
AI summary
Methods and apparatus are provided for controlling a beam pattern of a sensor array. The apparatus includes a plurality of sensors, wherein a distance is defined between at least two of the sensors. A shape memory alloy (“SMA”) is coupled to at least one of the sensors. The SMA is controllably deformable to vary the distance between the sensors.