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Microwave imaging helps FAA foil hijackers

Bioeffects Seen

Lyman J. Hardeman · 1971

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Early FAA microwave imaging for hijacker detection established precedents for routine EMF exposure in security screening.

Plain English Summary

Summary written for general audiences

This 1971 research examined how the Federal Aviation Administration used microwave imaging technology to detect weapons and prevent aircraft hijackings. The study focused on phase-locked antenna systems and holographic techniques for security screening applications.

Why This Matters

This research represents an early example of how microwave technology became integrated into public safety systems during the height of airline hijacking concerns in the 1970s. While the FAA's security applications may seem distant from health concerns, the reality is that microwave imaging systems expose both operators and the public to electromagnetic fields. The science demonstrates that any microwave-based detection system creates EMF exposure, and understanding these early implementations helps us recognize how security technologies have evolved into today's millimeter wave body scanners at airports. What this means for you is that the normalization of microwave technology for security purposes established precedents for EMF exposure that we now encounter routinely in transportation hubs.

Figures from the Original Paper

Diagrams extracted from the original research document.

diagramPage 1 - AI-described figure: A block diagram illustrating a microwave imaging system for detecting concealed weapons.
p. 1 of the original PDF
chartPage 2 - AI-described figure: A chart showing dissipation factor vs. frequency for RT/duroid materials.
p. 2 of the original PDF

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 70 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 70 GHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Study Details

A unique method for detecting concealed guns has been demonstrated by Nabil Farhat and Wayne Guard of the University of Pennsylvania Moore School of Electrical Engineering. Their prototype system has successfully penetrated a tweed jacket to produce a visual image of a small pistol.

The metal object to be imaged is luminated with 70 GHz (X = 4.3 mm) radiation produced by a reflex k...

The researchers successfully detected a small gun through a tweed jacket. The phasigram was generate...

The weapon detector system has potential applications by the FAA as an anti-hijacking device. Real-time phasigram and image construction will require an array of detectors positioned over the aperture.

Cite This Study
Lyman J. Hardeman (1971). Microwave imaging helps FAA foil hijackers.
Show BibTeX
@article{microwave_imaging_helps_faa_foil_hijackers_g3622,
  author = {Lyman J. Hardeman},
  title = {Microwave imaging helps FAA foil hijackers},
  year = {1971},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

The FAA employed phase-locked antenna systems and holographic microwave imaging techniques to detect concealed weapons on passengers and prevent aircraft hijackings during the early 1970s security crisis.
These early detection systems generated microwave radiation to penetrate clothing and create images, exposing both security operators and screened passengers to electromagnetic fields during the scanning process.
Microwave frequencies could penetrate clothing and other materials while reflecting off metal objects, making them ideal for detecting concealed weapons without physical searches during the hijacking epidemic.
Holographic processing allowed the microwave imaging systems to create detailed three-dimensional representations of concealed objects, improving weapon detection accuracy compared to simple reflection-based methods.
Today's millimeter wave body scanners evolved from these early microwave detection concepts, though modern systems use higher frequencies and more sophisticated imaging algorithms for enhanced security screening.