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Determination of Far-Field Antenna Patterns from Near-Field Measurements

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Johnson RC, Ecker HA, Hollis JS · 1973

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This foundational 1973 research established measurement techniques still used today to assess EMF exposure from antennas.

Plain English Summary

Summary written for general audiences

This 1973 technical study developed three methods for measuring antenna radiation patterns at close range instead of requiring large distances. Researchers created techniques to predict how antennas would perform in real-world conditions without needing massive testing facilities. This foundational work helped establish how we measure and understand electromagnetic field exposure from antennas today.

Why This Matters

While this appears to be purely technical research, this 1973 study represents foundational work that shapes how we understand EMF exposure today. The techniques developed here for measuring antenna patterns in near-field conditions directly influence how we assess radiation exposure from cell towers, WiFi routers, and other wireless devices in our daily environment. What makes this significant is that these measurement methods help determine the actual EMF exposure levels people experience from antennas operating close to where we live and work. The reality is that most EMF exposure assessments today rely on principles established in studies like this one. Understanding antenna behavior in near-field conditions is crucial because that's exactly where human exposure occurs - not in the theoretical far-field, but in the immediate vicinity of transmitting devices.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
Johnson RC, Ecker HA, Hollis JS (1973). Determination of Far-Field Antenna Patterns from Near-Field Measurements.
Show BibTeX
@article{determination_of_far_field_antenna_patterns_from_near_field_measurements_g6307,
  author = {Johnson RC and Ecker HA and Hollis JS},
  title = {Determination of Far-Field Antenna Patterns from Near-Field Measurements},
  year = {1973},
  
  
}

Quick Questions About This Study

Near-field measurements assess antenna radiation patterns at close distances rather than far away. This technique allows researchers to predict antenna behavior in real-world conditions where people are actually exposed to electromagnetic fields from wireless devices.
Far-field measurements require impractically long distances, often miles away. Moving large antennas to testing ranges is expensive and time-consuming. Near-field techniques solve these problems by measuring close-up and calculating far-field performance mathematically.
A scanning probe measures the electromagnetic field's amplitude and phase across the antenna aperture. This data is then mathematically transformed to predict how the antenna will radiate at greater distances, providing accurate far-field pattern information.
This method uses a large reflector and feed system to create uniform electromagnetic waves near the test antenna. It simulates far-field conditions at close range, allowing accurate pattern measurements without requiring vast testing distances.
The test antenna is first focused within the near-field region for pattern measurements, then mathematically refocused to infinity. This technique provides far-field pattern data while working at practical, manageable distances in laboratory settings.