Sub-millimeter Wave Detection for Non-metallic Concealed Objects
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Solution Overview
Problem
Existing methods for detecting concealed objects, such as contraband or explosives, within obscuring mediums like clothing are limited, particularly for non-metallic materials, and millimeter wave systems face bandwidth restrictions and image quality issues.
Innovation Solution
The use of sub-millimeter wave (SMMW) and ultrasonic systems, operating in passive or active modes, with wideband frequencies and hyperspectral imaging techniques to detect and identify objects by processing RF signals and creating high-resolution images and material identification data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal detectors are used to detect concealed objects, then metallic objects can be detected, but non-metallic objects (plastic or liquid materials) cannot be detected
Solution Approach 1:
The patent changes the detection parameter from electrical conductivity (metal detectors) to dielectric properties and physical state (sub-MMW and ultrasonic systems). By measuring dielectric constant, loss tangent, and acoustic impedance, the system can distinguish between metallic, non-metallic, liquid, and solid materials, thereby expanding material detection range while maintaining reliability
Solution Approach 2:
The patent replaces the electromagnetic induction-based metal detection system with a combined sub-MMW and ultrasonic detection system. This substitution enables detection of non-metallic materials by utilizing dielectric properties and acoustic wave interactions, which are effective for plastic, liquid, and other non-conductive materials
2Reliability
If millimeter wave frequencies below 100 GHz are used for people screening, then concealed objects can be detected through clothing, but bandwidth availability is limited and image quality is degraded
Solution Approach 1:
The patent changes the frequency parameter from traditional MMW (below 100 GHz) to sub-MMW range (100-300 GHz). This frequency elevation provides several advantages: increased bandwidth availability, improved resolution for object identification, and enhanced penetration characteristics. The higher frequency enables capture of more spectral information while maintaining the ability to detect concealed objects through clothing
Solution Approach 2:
The patent adds a spectral dimension to the detection by utilizing the wide bandwidth of sub-MMW frequencies. Instead of relying solely on spatial imaging, the system captures frequency-domain information across a broad spectrum, enabling material identification through spectral signatures and improving overall detection capability
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
Enables effective detection and identification of concealed objects, including non-metallic materials, with improved image quality and material characterization, overcoming bandwidth limitations and enhancing detection capabilities.
Implementation Method 1
an antenna configured to receive an RF signal in the sub-millimeter wave range, the RF signal having been emitted by an object
Implementation Method 2
a detector configured to convert the RF signal into an electrical signal
Implementation Method 3
a signal integrator configured to integrate the electrical signal and provide an integrated signal over an observation period
Implementation Method 4
processing the received signals using at least one of a fast Fourier transform and a hyperspectral imaging technique to extract object information
Implementation Method 5
processing the received signals using at least one of a fast Fourier transform and a hyperspectral imaging technique
Implementation Method 6
a frequency synthesizer configured to generate signals in a wideband spectrum, the signals having a Frequency Modulated Continuous Wave waveform
Implementation Method 7
a frequency synthesizer configured to generate signals in a wideband spectrum
Implementation Method 8
at least one transmit antenna configured to transmit the signals
Implementation Method 9
at least one receive antenna configured to receive reflected signals, the reflected signals having been reflected by an object
Implementation Method 10
creating an image of the detected object based on the extracted object information
Data Source
AI summary
Active and passive sub-millimeter wave RF and ultrasonic systems can be used to detect a concealed object, such as an object concealed under the clothing of a subject, and identify material properties of the object. A concealed object detection system can include an antenna configured to receive an RF signal in the sub-millimeter wave range, the RF signal having been emitted by an object, a detector configured to convert the RF signal into an electrical signal, a signal integrator configured to integrate the electrical signal and provide an integrated signal over an observation period and a processor configured to extract object information from the integrated signal. An object indication device provides an indication of a detected object and material properties of the detected object based on the extracted object information. The extracted object information can include object image data and object material identification data.