Antenna Radiator Layout for RF Isolation and Capacitive Sensing
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Solution Overview
Problem
The interference between radio frequency signals and capacitive sensing signals in electronic devices, such as smartphones, affects detection accuracy and flexibility of the capacitive sensor due to shared transmission paths and the need for isolation components like capacitors or inductors.
Innovation Solution
The capacitive sensing path is separated from the radio frequency path by leading a conducting wire from the minimum-voltage point on the radiator to the sensor chip, eliminating the need for isolation components and reducing interference, while using multiple antenna units as sensor pads to increase detection area and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lumped component such as a capacitor or an inductor is connected to the path to isolate radio frequency signal and capacitive sensing signal, then the two signals can be separated and transmitted to radio frequency path and sensor path respectively, but the radio frequency signal and capacitive sensing signal still interfere with each other when being transmitted in the same path, which affects detection accuracy of the capacitive sensor
Solution Approach 1:
The patent divides the transmission path into separate radio frequency path and sensor path by leading a conducting wire from the minimum-voltage point on the radiator directly to the sensor chip. This segmentation eliminates the need for lumped components and prevents signal interference, thereby improving both signal isolation and detection accuracy simultaneously.
2Reliability
If a lumped component such as a capacitor or an inductor is connected to the path, then radio frequency signal and capacitive sensing signal can be isolated, but the structure becomes more complex and debugging flexibility is reduced
Solution Approach 1:
The patent extracts the capacitive sensing path from the radio frequency path by leading a conducting wire from the minimum-voltage point on the radiator directly to the sensor chip. This removes the need for isolation components like capacitors or inductors, simplifying the structure while maintaining signal isolation and improving debugging flexibility.
3Device complexity
If the conducting wire is led out from the minimum-voltage point on the radiator, then the capacitive sensing path is separated from the radio frequency path and isolation components are not needed, but this configuration must be precisely implemented to maintain antenna performance
Solution Approach 1:
The patent uses the minimum-voltage point on the radiator as an intermediary connection point. This specific location serves as an optimal compromise point that allows separation of the capacitive sensing path from the radio frequency path while minimizing impact on antenna performance. The conducting wire is led out from this intermediary point to achieve both structure simplification and maintained antenna functionality.
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 improves detection accuracy and sensitivity of the capacitive sensor by reducing interference and allowing for flexible radio frequency path debugging, while also enabling precise object location and increased detection distance.
Implementation Method 1
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
Data Source
AI summary
An 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.