Antenna Radiator Capacitive Sensing With RF Path Isolation
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Solution Overview
Problem
Existing capacitive sensors in electronic devices face interference between radio frequency and capacitive sensing signals due to shared paths, which degrades detection accuracy and sensitivity, and requires additional isolation components, complicating the structure and debugging of the radio frequency path.
Innovation Solution
The solution involves using a conducting wire to connect a sensor chip to a minimum-voltage point on an antenna radiator, separating the capacitive sensing path from the radio frequency path, allowing the capacitive sensing current to be transmitted directly to the sensor chip, thereby reducing interference and eliminating the need for isolation components, and utilizing multiple antenna units to increase the detection area and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the antenna radiator is used as a sensor pad for capacitive sensing, then space utilization is improved, but signal interference between radio frequency and capacitive sensing paths increases
Solution Approach 1:
The patent segments the antenna structure by identifying and utilizing the minimum-voltage point on the radiator to create a separate capacitive sensing path. This segmentation allows the radiator to serve dual functions while maintaining signal isolation through the distinct current paths.
Solution Approach 2:
The minimum-voltage point on the radiator acts as an intermediary connection point that enables the capacitive sensing path to access the radiator without interfering with the radio frequency path. This intermediary point serves as a bridge that separates the two functional paths.
2Object-affected harmful factors
If isolation components are added to separate radio frequency and capacitive sensing signals, then signal interference is reduced, but device structure becomes more complex
Solution Approach 1:
The patent extracts the capacitive sensing function from the radio frequency path by utilizing the minimum-voltage point on the radiator. This extraction eliminates the need for isolation components while maintaining signal separation, as the capacitive sensing current is naturally isolated at the minimum-voltage point.
Solution Approach 2:
The antenna radiator serves its own dual function by providing both radio frequency transmission and capacitive sensing capabilities. The minimum-voltage point on the radiator self-provides the isolation function that would otherwise require external components, making the system self-sufficient.
3Device complexity
If the same path is used for both radio frequency and capacitive sensing signals, then device complexity is reduced, but detection accuracy deteriorates
Solution Approach 1:
The patent segments the signal paths by utilizing the minimum-voltage point to create distinct capacitive sensing and radio frequency paths. This segmentation maintains structural simplicity while improving detection accuracy through natural signal separation at the minimum-voltage point.
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 approach enhances detection accuracy and sensitivity by isolating the capacitive sensing path from the radio frequency path, simplifying the structure, and improving debugging flexibility, while allowing for longer detection distances and precise location determination of objects.
Implementation Method 1
A capacitive sensor (capacitive sensor) includes a sensor pad and a sensor chip, and can detect a proximity or a distance level of a detected object based on a capacitance change between the detected object and the sensor pad.
Implementation Method 2
The sensor chip is electrically connected to a minimum-voltage point on the first radiator by a conducting wire.
Data Source
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AI summary
This application provides an electronic device. The electronic device includes a first antenna unit. The first antenna unit includes a first radiator, the first radiator is configured to receive and transmit a radio frequency signal, and the first radiator is further configured to sense capacitance or a capacitance change between the first radiator and a detected object when the detected object approaches. The electronic device further includes a sensor chip. The sensor chip is configured to obtain the capacitance or the capacitance change, to determine a proximity of the detected object relative to the first radiator, and the sensor chip is electrically connected to a minimum-voltage point on the first radiator by a conducting wire. In the foregoing technical solution, the conducting wire is led out from the minimum-voltage point on the radiator and connected to the sensor chip, so that a capacitive sensing path of a sensor can be separated from a radio frequency path of the antenna unit. This reduces or avoids mutual interference between the capacitive sensing path and the radio frequency path, and improves detection accuracy of the sensor.