RF Antenna Proximity Detection via Impedance Mismatch
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Solution Overview
Problem
Existing touchless actuation systems for electric loads require additional sensor components, increasing cost and size, and are affected by antennas, which complicates proximity detection and actuation precision.
Innovation Solution
A device comprising a radiofrequency (RF) communications module, a directional coupler, and a processor that uses reflected electrical signals to determine user proximity and provide actuation commands without the need for separate sensors, utilizing impedance mismatch analysis to control electric loads wirelessly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sensor means are added for touchless actuation, then touchless control capability is improved, but device complexity and cost increase
Solution Approach 1:
The antenna is made to serve dual functions: radiating RF signals for communication and detecting user proximity through impedance mismatch analysis. This eliminates the need for separate sensor components while maintaining touchless control capability, directly resolving the contradiction between ease of operation and device complexity
Solution Approach 2:
The proximity detection function is merged with the existing RF communication antenna by analyzing reflected electrical signals through a directional coupler. This combination approach allows touchless actuation without adding separate sensor hardware, reducing device complexity while preserving touchless control functionality
2Ease of operation
If sensor means are added for touchless actuation, then touchless control capability is improved, but manufacturing cost increases
Solution Approach 1:
The antenna performs both RF signal radiation and proximity detection functions, eliminating the need for additional sensor components that would increase manufacturing cost. This multi-functionality approach maintains touchless control while simplifying manufacturing
Solution Approach 2:
The system uses its own transmitted RF signals to detect user proximity through impedance mismatch analysis via the directional coupler. This self-service approach eliminates the need for separate active sensors, reducing component count and manufacturing cost while enabling touchless control
3Measurement precision
If proximity sensor is used for user detection, then user proximity detection is improved, but antenna radiation control becomes difficult
Solution Approach 1:
The directional coupler provides feedback on the impedance mismatch caused by user proximity to the antenna. This feedback mechanism allows the system to detect user presence precisely while maintaining control over antenna radiation by monitoring signal reflections rather than requiring separate sensor control mechanisms
4Ease of operation
If separate sensor components are used, then touchless detection capability is improved, but device size increases
Solution Approach 1:
The antenna serves dual purposes as both an RF communication element and a proximity detection sensor. This eliminates the need for separate sensor components that would increase device size, maintaining touchless detection capability while minimizing device volume
Solution Approach 2:
The proximity detection functionality is merged into the existing antenna structure by analyzing reflected RF signals through the directional coupler. This integration approach enables touchless detection without adding separate sensor hardware, thereby reducing device size
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 precise and reliable touchless control of electric loads with reduced energy consumption and false positives, improving user interaction and manufacturing simplicity by eliminating the need for additional sensor components and antenna interference.
Implementation Method 1
the mismatch of the antenna due to the proximate presence of the user - e.g. in the order of centimeters, for example 15 centimeters or less, preferably 5 centimeters or less- results in the non-radiation of part of the electrical signals
Implementation Method 2
the at least one processor and the RF communications module are both configured to provide electrical signals for radiation to the antenna
Data Source
Figure 1
Figure 2~3
AI summary
A device for actuating an electric load, comprising: an antenna; a radiofrequency (RF) communications module electrically coupled with the antenna; at least one processor electrically coupled with the RF communications module; and a directional coupler at least via which the RF communications module is coupled with the antenna; the at least one processor and the RF communications module are both configured to provide electrical signals for radiation to the antenna, the electrical signals for radiation comprising both data and pulse signals; the at least one processor is further configured to at least determine whether a user is proximate to the antenna by processing part of the electrical signals for radiation that are not radiated by the antenna and are reflected to the directional coupler, and further configured to provide a command for actuation of at least one electric load based on the determination made. Also, a system comprising one or more said devices, and a method for actuating at least one electric load.