Dual Patch Antenna Layout for Stable In-Car Gesture Sensing
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Solution Overview
Problem
Existing radio-frequency gesture-detecting systems in motor vehicles struggle to maintain consistent signal strength when a target, such as a user's foot, is positioned aligned or offset laterally relative to the antenna, leading to reduced detection accuracy.
Innovation Solution
A device with two radio-frequency antennas, a T-antenna and a rectangular antenna, each with specific radiation patterns, is integrated into a printed circuit board, where the T-antenna has side lobes oriented parallel to the board and the rectangular antenna has side lobes oriented orthogonal to the board, reducing signal intensity variation due to target placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single patch antenna is used for gesture detection, then the device structure is simple, but the signal intensity varies significantly when the target is positioned aligned or offset laterally relative to the antenna
Solution Approach 1:
The single antenna is segmented into two distinct antenna elements: a first antenna with side lobes oriented in a first direction and a second antenna with side lobes oriented in a second direction. This segmentation allows each antenna to cover different spatial zones, and their combined signals provide consistent detection accuracy regardless of target lateral position.
Solution Approach 2:
The two antennas are designed with asymmetric orientation of their radiation patterns. The first antenna's side lobes are oriented in a first direction while the second antenna's side lobes are oriented in a second direction, creating complementary coverage patterns that together eliminate the directional sensitivity issue of a single antenna.
2Measurement precision
If the antenna radiation pattern is optimized for one target position, then detection accuracy is improved for that position, but detection performance deteriorates for other positions
Solution Approach 1:
The antenna system is designed with multi-functionality to serve multiple detection zones simultaneously. The first antenna covers a first detection zone while the second antenna covers a second detection zone, and both zones overlap to provide universal coverage that maintains consistent detection accuracy across different target positions.
Solution Approach 2:
The solution transitions from a single-directional radiation pattern to a multi-directional coverage by introducing a second antenna with side lobes oriented in a different direction. This adds a dimensional aspect to the radiation coverage, creating complementary detection zones that together provide omnidirectional-like performance.
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 configuration enhances detection accuracy by minimizing signal intensity variation regardless of the target's alignment or lateral offset, allowing for effective gesture detection while maintaining a compact and cost-effective design suitable for automotive applications.
Implementation Method 1
transmission of a radio-frequency signal and analysis of a return signal sent back by the environment
Implementation Method 2
determining a Doppler frequency related to an instantaneous velocity of the target
Implementation Method 3
determining a phase shift related to an instantaneous position of the target
Data Source
AI summary
A device (900) for transmitting and/or receiving radio-frequency signals, which is intended to be integrated into a gesture-detecting system in a motor vehicle, and which comprises:a printed circuit board (930);at least one patch antenna (910), called the T-antenna, comprising superposed a first metal excitation surface and a first ground plane, at least one of the first ground plane and the first metal excitation surface having a T-shaped region, so that the radiation pattern of the T-antenna has two high-radiation side lobes, which are oriented substantially parallel to the plane of the printed circuit board, and separated by a low-radiation central zone; andat least one patch antenna (920), called the rectangular antenna, comprising superposed a second metal excitation surface and a second ground plane, the second metal excitation surface comprising a rectangular region having a general rectangle shape and configured so that the radiation pattern of the rectangular antenna has two high-radiation side lobes, which are oriented substantially orthogonal to the plane of the printed circuit board, and separated by a low-radiation central zone.