Foreign Object Detection Using Phase Difference Analysis
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Solution Overview
Problem
Existing systems fail to effectively detect foreign objects, such as skimming devices, mounted in the near range of input means for authentication in service machines, which can lead to unauthorized data retrieval and tampering.
Innovation Solution
An apparatus utilizing a circularly polarized patch antenna generates a standing wave and detects phase differences between the supplied oscillating signal and reflection signals to identify foreign objects, employing a coupler to couple out reflection signals and a detection device to determine phase differences, ensuring high directional sensitivity and operation within the ISM band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection methods are used, then the system structure remains simple, but the detection precision and reliability are insufficient for identifying foreign objects in the near range
Solution Approach 1:
The patent employs dynamic signal processing techniques, including phase modulation and correlation detection, to enhance the detection of foreign objects. The system dynamically adjusts its detection parameters and uses time-varying signals to improve sensitivity and precision in identifying foreign objects within the near range.
Solution Approach 2:
The patent introduces an intermediary detection mechanism that uses a reference signal and correlation processing to mediate between the transmitted signal and the received signal. This intermediary approach enables precise detection of foreign objects by comparing phase differences and correlation values, thereby improving measurement precision without excessively complicating the system.
2Reliability
If the detection range is extended to cover the near range, then the security coverage is improved, but the false detection rate increases
Solution Approach 1:
The patent implements feedback mechanisms through correlation detection and phase comparison, where the detected signals are continuously compared against reference patterns. This feedback loop enables the system to distinguish between genuine foreign objects and false targets, thereby improving detection reliability while reducing the false detection rate in the extended near range.
Solution Approach 2:
The patent utilizes parameter changes in the form of phase modulation and frequency analysis to enhance detection capability. By analyzing phase differences and correlation values across multiple signal parameters, the system can reliably identify foreign objects in the near range while filtering out false detections through multi-parameter verification.
3Measurement precision
If phase difference detection is used, then the directional sensitivity is improved, but the device complexity increases due to additional signal processing requirements
Solution Approach 1:
The patent replaces complex mechanical or hardware-based directional sensing systems with signal processing-based phase difference detection. By using electronic correlation and phase comparison techniques, the system achieves high directional sensitivity without the need for complex mechanical structures, thereby improving measurement precision while managing device complexity through software-based solutions.
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 solution provides effective detection of foreign objects, enhancing security by identifying tampering devices and preventing unauthorized access, with high sensitivity and reliability across the usable frequency region.
Implementation Method 1
an antenna (6) for generating a standing wave upon reception of an oscillating signal
Implementation Method 2
a coupler (2) arranged to couple out the reflection signal received with the antenna (6) to the detection device
Implementation Method 3
a detection device (8) arranged to detect a phase difference between the oscillating signal and the reflection signal that is coupled out by the coupler (2)
Implementation Method 4
The frequency of the oscillating signal and the geometry of the antenna are arranged such that the monitoring region of the apparatus is in a region where the reception sensitivity of the antenna is large
Data Source
AI summary
The apparatus for detecting a foreign object mounted in the near range of an input means used for identification and/or authentication includes at least a coupler. The coupler is arranged to supply an oscillating signal to two input terminals of an antenna for generating a standing wave, to supply the oscillating signal with a predetermined level to a detection device, and to couple out, for the detection device, a reflection signal received by the antenna. Furthermore, the coupler is arranged to detect a phase difference between the supplied oscillating signal with the predetermined level and the reflection signal that is coupled out, in order to detect the foreign object.