Open-Electrode Resonant Ranging for Low-Power Material Detection
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Solution Overview
Problem
Existing proximity detection systems in mobile devices suffer from high power consumption, false positive detections, fixed minimum detection ranges, and limited adaptability, making them inefficient for compliance with FCC regulations and suitable for small form factor devices.
Innovation Solution
A low-frequency detection and ranging (LFDAR) system using an open electrode, alternating current voltage source, and resonant circuit that determines object material class through amplitude and phase differences, allowing for adjustable detection ranges and low power consumption, and can be adapted for various devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional proximity detectors are used, then detection function is provided, but power consumption is high and false positive detections occur
Solution Approach 1:
The patent combines the proximity detection function with existing RF communication antennas and circuits, eliminating the need for separate dedicated proximity detection hardware. The same antenna structure serves dual purposes: RF communication and proximity sensing through electromagnetic coupling analysis, thereby reducing overall power consumption while maintaining detection reliability.
Solution Approach 2:
The existing RF antenna system is made multi-functional by enabling it to perform both its primary communication function and secondary proximity detection function. The system analyzes electromagnetic coupling characteristics during normal RF operation to detect proximity, allowing one system to serve multiple purposes without additional power-consuming components.
2Adaptability or versatility
If traditional proximity detectors are used, then detection is provided, but minimum detection range is fixed
Solution Approach 1:
The system dynamically adjusts detection parameters and ranges based on real-time electromagnetic coupling measurements. By analyzing the strength and characteristics of coupling between antennas at different distances, the system can adaptively determine appropriate detection thresholds and ranges, providing flexible detection capabilities without requiring fixed physical constraints or additional circuitry.
Solution Approach 2:
The patent changes the operational parameters of the RF system to enable proximity detection at varying ranges. By monitoring electromagnetic coupling strength across different frequency and power levels, the system can detect proximity at multiple distance thresholds, transforming a static detection system into one with adjustable range parameters using existing components.
3Reliability
If additional circuitry is added for ranging and detection, then detection capability is improved, but device form factor increases
Solution Approach 1:
The patent merges proximity detection circuitry with the existing RF communication subsystem, using the same antennas, amplifiers, and signal processing circuits for both communication and detection functions. This integration eliminates the need for separate detection hardware, maintaining high detection capability while preserving compact device form factors suitable for smartphones and wearables.
Solution Approach 2:
Existing RF communication components are made multi-functional to perform both data transmission and proximity detection. The antenna system, power amplifiers, and signal processors handle dual tasks, eliminating the volume increase that would result from adding dedicated detection circuitry while maintaining robust detection capabilities.
4Measurement precision
If specific antenna shapes and orientations are used, then detection accuracy is improved, but device adaptability is reduced
Solution Approach 1:
The system uses excessive electromagnetic field analysis by examining multiple coupling characteristics and signal parameters beyond what is strictly necessary for basic detection. This over-analysis approach allows the system to achieve high accuracy across various antenna configurations and orientations, compensating for suboptimal physical arrangements through sophisticated signal processing of the electromagnetic coupling data.
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
The LFDAR system provides extreme sensitivity at close ranges, reduces electromagnetic radiation emissions, and is agnostic to frequency and antenna shapes, making it suitable for small form factor products while minimizing power consumption and false detections.
Implementation Method 1
a resonant circuit coupled to the open electrode, the resonant circuit configured to oscillate when an object is within a detection distance of the open electrode
Implementation Method 2
an alternating current (AC) voltage source configured to supply an excitation voltage to the open electrode at an excitation frequency
Data Source
AI summary
Embodiments are disclosed for a low-frequency detection and ranging. In an embodiment, an apparatus comprises: an open electrode; an alternating current (AC) voltage source configured to supply an excitation voltage to the open electrode at an excitation frequency; a resonant circuit coupled to the open electrode, the resonant circuit configured to oscillate when an object is within a detection distance of the open electrode; one or more processors configured to: obtain time domain samples of an output voltage of the resonant circuit when the resonant circuit is oscillating; convert the time domain samples into frequency domain samples; for each frequency domain sample, determine an amplitude difference and a phase difference as compared to an amplitude and phase of the excitation voltage; and determine a material class of the object based on the amplitude difference and the phase difference.