Patch Antenna Array Shaping for Uniform Vital Sign Radar Coverage
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Solution Overview
Problem
Existing radar antenna systems struggle to maintain consistent power levels for monitoring vital signs of individuals regardless of their location within a closed environment, such as a room or vehicle, particularly in corner areas where power drops significantly due to limited opening angles and free-space attenuation.
Innovation Solution
A radar antenna array system is designed with a configuration of microstrip patch antennas that shape the farfield pattern in both the E-plane and H-plane using series- and parallel-feeding techniques, creating a heart-shaped radiation pattern with enhanced power in corner areas and minimized power in central areas, utilizing a 3x3 array of patches with specific amplitude and phase shifts to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional radar antenna systems are used with standard radiation patterns, then the radiation power is sufficient in central areas, but the radiation power drops significantly in corner areas due to limited opening angles and free-space attenuation
Solution Approach 1:
The patent applies local quality by creating a non-uniform radiation pattern where different spatial regions receive different radiation power levels. Specifically, the antenna array is configured to provide enhanced radiation power in corner areas (where it was previously insufficient) while reducing power in central areas (where it was previously excessive), thereby achieving uniform monitoring coverage across all regions of the monitored space
Solution Approach 2:
The patent employs asymmetry by designing an asymmetric radiation pattern that deliberately deviates from the conventional symmetric omnidirectional pattern. The antenna array uses specific amplitude and phase weighting to create lobes directed toward corner areas, making the radiation distribution asymmetric to compensate for the geometric asymmetry of corner positions relative to the ceiling-mounted antenna
2Power
If the antenna array configuration is optimized for corner coverage, then radiation power in corners is enhanced, but radiation power in central areas increases excessively
Solution Approach 1:
The patent applies feedback by using the signal processing unit to analyze the radiation pattern and adjust the amplitude and phase weights of individual antenna elements. This feedback mechanism allows the system to optimize the radiation pattern in real-time, enhancing power in corner areas while simultaneously suppressing excessive power in central areas, thereby achieving uniform power distribution across the monitored space
Solution Approach 2:
The patent employs parameter changes by systematically varying the amplitude and phase parameters of each antenna element in the array. By adjusting these parameters, the radiation pattern is transformed from a conventional symmetric pattern to a customized pattern that provides uniform power distribution, specifically compensating for the power drops in corner areas while controlling power levels in central areas
3Measurement precision
If standard antenna arrays are used, then the system structure is simple, but the monitoring precision in corner areas deteriorates due to power drops
Solution Approach 1:
The patent applies segmentation by dividing the antenna array into multiple independently controllable antenna elements, each capable of having its amplitude and phase parameters adjusted separately. This segmentation allows the system to create a complex radiation pattern with multiple lobes directed toward different regions (including corners) by combining the outputs of individual elements, thereby improving detection precision in corner areas while maintaining a modular and manageable system structure
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 system ensures reliable monitoring of vital signs by maintaining higher radiation power in corner areas, compensating for power drops, and providing consistent performance across the monitored space.
Implementation Method 1
an array of three-by-one patches configured to shape the farfield pattern in the E-plane by series-feeding, or an array of one-by-three patches configured to shape the farfield pattern in the H-plane by parallel-feeding
Data Source
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AI summary
The present invention is directed to a patch antenna array system for monitoring vital signs of people in a closed environment, the patch antenna array system comprising three patches, the farfield pattern of which is shaped in the E-plane by series-feeding and in the H-plane by parallel-feeding to attain a heart-shaped pattern compensating free-space losses due to larger distances.