Drop in power in a directed microwave beam?

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Discussion Overview

The discussion revolves around the behavior of power in a directed microwave beam as a function of distance. Participants explore how distance affects power drop, considering different scales and contexts.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that power drop may follow the inverse square law at large distances.
  • Another participant counters that for small distances, this may not hold true.
  • A participant inquires about the definitions of short and large distances in this context.
  • It is noted that the typical length scale is related to the antenna diameter and wavelength, influencing the applicability of the inverse square law.
  • Further clarification indicates that at distances greater than five times the length scale, the inverse square law is a reasonable approximation, while below that, the relationship may vary.
  • In the intermediate range, the behavior of power drop remains uncertain and may not conform strictly to either case.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of the inverse square law at various distances, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

The discussion highlights the dependence on specific definitions of distance and the limitations of the inverse square law based on the physical characteristics of the microwave beam.

Patrick Pihl
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Would it be a drop in power as the square of the distance in a directed microwave beam? Thanks!
 
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For small distances: probably not.
For very large distances: yes.

The typical length scale is (antenna diameter)^2 / (wavelength), focusing something over a longer distance does not work.
 
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Thanks! What would be a short / large distance in this context?
 
Did you see my comment about the length scale? If you are at 5+ times this length scale the inverse squared distance is a good scaling law. If you are below that length, it does not have to be a good approximation. It might be, but that depends on the beam then. In between, things are in between those two cases.
 
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