Antenna Transmission Structure for RF-Isolated Proximity Sensing
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Solution Overview
Problem
Current proximity sensing systems in electronic devices, which use an antenna as the sensing electrode, face accuracy issues due to interference from radio-frequency signals, leading to incorrect proximity judgments and unnecessary power reductions, affecting both device performance and user health.
Innovation Solution
A transmission structure incorporating a radio-frequency short-circuit element and a transmission line with high impedance, preventing radio-frequency signals from reaching the proximity sensing circuit, and a selection circuit to adapt to different frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the antenna is used as the sensing electrode for proximity sensing, then the cost is reduced and no extra metal member is required, but the radio-frequency signal transmitted through the antenna interferes with the proximity sensing circuit, degrading sensing accuracy
Solution Approach 1:
The transmission line is segmented into multiple sections with different impedance characteristics. A first transmission line section with first impedance connects the antenna to a radio-frequency short-circuit element, while a second transmission line section with second impedance connects the short-circuit element to the proximity sensing circuit. This segmentation allows different portions of the transmission path to have optimized impedance values for their respective functions.
Solution Approach 2:
The patent changes the impedance parameter along the transmission path by using transmission line sections with different impedance values. The first impedance is designed to be different from the second impedance, creating an impedance transformation effect that helps isolate the radio-frequency signal from the proximity sensing circuit while maintaining proper signal transmission to the antenna.
2Device complexity
If a transmission line directly connects the antenna to the proximity sensing circuit, then the circuit complexity is reduced, but the radio-frequency signal is transmitted to the proximity sensing circuit causing false proximity detection and unnecessary power reduction
Solution Approach 1:
A radio-frequency short-circuit element is introduced as an intermediary component between the antenna and the proximity sensing circuit. This short-circuit element, connected through transmission line sections with specific impedances, acts as a mediator that blocks radio-frequency signals from reaching the proximity sensing circuit while allowing the proximity sensing function to operate correctly.
3Measurement precision
If the radio-frequency signal is blocked from the proximity sensing circuit, then sensing accuracy is improved, but additional components are required increasing device complexity
Solution Approach 1:
The transmission line structure serves multiple functions: it provides the electrical connection between the antenna and the proximity sensing circuit, transforms impedance to optimize signal transmission, and blocks radio-frequency signals from interfering with the proximity sensing circuit. By designing the transmission line with specific impedance characteristics, a single component structure achieves multiple objectives without requiring additional blocking components.
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 solution enhances the accuracy of proximity sensing by isolating radio-frequency signals from the antenna, preventing interference and ensuring accurate human body proximity detection without unnecessary power reductions.
Implementation Method 1
By coupling the at least one radio-frequency short-circuit element to the transmission line, the transmission path between the antenna and the proximity sensing circuit has high impedance for avoiding the radio-frequency signal of the antenna from being transmitted to the proximity sensing circuit
Data Source
AI summary
The present application provides a transmission structure of an antenna and a proximity sensing circuit. The transmission structure includes a transmission line and at least one radio-frequency short-circuit element, a first coupling end of the transmission line is coupled to an antenna, and a second coupling end of the transmission line is coupled to a proximity sensing circuit, and the at least one radio-frequency short-circuit element is coupled between the transmission line and a ground, and is located between the antenna and the proximity sensing circuit. Utilizing the at least one radio-frequency short-circuit element in conjunction with the transmission line so that the transmission path between the antenna and the proximity sensing circuit has the high impedance, and hence preventing a radio-frequency signal from the antenna from affecting the sensing accuracy of the proximity sensing circuit.