Passive Millimeter Wave Detection Using Digital Beamforming
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Solution Overview
Problem
Current security scanning technologies, such as metal detectors, X-ray machines, and millimeter wave imaging systems, are inefficient, invasive, and costly, and struggle with detecting small or well-hidden items, particularly in near-field scenarios, due to limitations in resolution, sensitivity, and operational constraints.
Innovation Solution
A passive detection apparatus using a plurality of antenna elements arranged in an array, connected to a digital beamformer and processor, capable of generating static and complex images in real-time, allowing for non-invasive imaging of concealed objects through millimeter or sub-millimeter wave radiation, with enhanced sensitivity and depth of field, enabling detection of both metallic and non-metallic objects without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If millimetre wave imaging systems are used to detect concealed objects, then detection capability is improved, but system size and cost increase significantly
Solution Approach 1:
The system divides the detection task into multiple frequency bands (millimetre wave and sub-millimetre wave), with each band targeting specific types of concealed objects. The antenna array is segmented into multiple elements that can be independently controlled to focus on different regions and depths, reducing the complexity of any single antenna element while maintaining overall detection capability.
Solution Approach 2:
The patent replaces bulky mechanical scanning systems with electronic beamforming using digital signal processing. Instead of physically moving antennas or lenses, the system uses electronic phase control to steer and focus beams, dramatically reducing system size while maintaining or improving detection precision through software-based image reconstruction.
2Measurement precision
If millimetre wave imaging systems operate in near-field, then detection of concealed objects is improved, but depth of field becomes very limited
Solution Approach 1:
The system dynamically adjusts the focal depth by changing the phase and amplitude weights of individual antenna elements in real-time. This electronic focusing capability allows the system to switch between near-field and far-field operation modes, extending the effective depth of field from centimetres to metres while maintaining detection precision through adaptive beamforming.
Solution Approach 2:
The patent changes the operational parameters of the antenna array by adjusting frequency, phase, and amplitude across multiple elements. By sweeping through different frequency bands and modifying beamforming parameters, the system extends its depth of field and can detect objects at various distances without physical repositioning, effectively transforming the static near-field limitation into a dynamic multi-range capability.
3Measurement precision
If radiometric sensitivity is increased to detect small amounts of low atomic number metals, then detection sensitivity is improved, but system complexity and cost increase
Solution Approach 1:
The system uses a single antenna array that operates across multiple frequency bands (millimetre and sub-millimetre waves) to detect different types of materials. By tuning the frequency and adjusting beamforming parameters, the same hardware detects metallic objects, low atomic number metals, organic materials, and inorganic solids, eliminating the need for multiple specialized sensors and reducing overall system complexity.
Solution Approach 2:
The patent employs composite signal processing that combines data from multiple frequency bands and multiple antenna elements. This composite approach enhances radiometric sensitivity by integrating information across the spectrum, allowing detection of trace amounts of various materials with a unified system rather than requiring separate specialized detectors for each material type.
4Device complexity
If traditional security scanning procedures are used, then implementation simplicity is maintained, but detection efficiency and speed decrease
Solution Approach 1:
The system performs automated detection, imaging, and analysis without requiring manual frisking or opening of packages. The antenna array automatically scans the target area, the digital beamformer processes signals in real-time, and the system generates images that highlight concealed objects, providing self-service detection that eliminates labour-intensive manual procedures while maintaining operational simplicity through automated workflows.
Solution Approach 2:
The patent replaces manual security checking procedures with automated electromagnetic detection and image processing. Instead of physical frisking or visual inspection, the system uses millimetre and sub-millimetre wave radiation to automatically detect and locate concealed objects, dramatically increasing detection speed and efficiency while keeping the interface simple through automated image display and analysis tools.
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 apparatus provides efficient, non-invasive, and cost-effective imaging of concealed objects, improving detection sensitivity and operational flexibility, allowing for real-time imaging of static or moving objects, and enabling the detection of small or well-hidden items without the need for physical contact or extensive hardware.
Implementation Method 1
the receiver system being adapted to receive and digitise radiometric emissions from a target
Implementation Method 2
the beamformer being adapted to process the received information to focus upon a near field region of the antenna array
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3c
AI summary
A passive detection device is disclosed comprising a plurality of antennas, receivers, and a digital beamformer, wherein the antennas and receivers are adapted to receive radiation of millimetre wavelengths from a near field region, to process and digitise it. The beamformer is adapted to process the received information and to generate static image information relating to the region. An indication means is provided to indicate the presence of objects of interest. The beamformer is preferentially adapted to generate information simultaneously in a plurality of planes at different distances from the apparatus. The indication means may comprise an array of pixels along the length of the apparatus to display image information, and may use the multi- planar information to construct images of the region comprising data from a plurality of planes. The invention has utility in security scanning applications such as at airports or other locations where security detection equipment is employed.