Bell Telephone Laboratories - Lens Antenna
May 1946 Radio-Craft

May 1946 Radio-Craft

May 1946 Radio Craft Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Craft, published 1929 - 1953. All copyrights are hereby acknowledged.

At first look this antenna from Bell Telephone Laboratories appears to be a phased array, but in fact it is a "lens" that uses reflecting metal fins to direct incoming and outgoing radio waves into a narrow beam. This is a new approach to the standard method of using a curved (usually parabolic) reflective dish with a feedhorn. No detail is given about how, if at all, the phases of the received signals are phase-adjusted at the point they converge on the back-side waveguide feed. It is sort of akin to the Osgood optical lens used in lighthouses. Shortly after the end of World War II, Bell Telephone Labs began a major effort to interconnect the entire country with microwave relay stations to enhance efficiency and reliability of long distance telephone calls. Maybe it didn't matter. Bell Labs published many different infomercials in RF / microwave trade magazines like Radio-Craft from the 1940s through the 1960s.

Bell Telephone Laboratories - A "Searchlight" to Focus Radio Waves

Bell Telephone Laboratories Lens Antenna, May 1946, Radio-Craft - RF CafeIn the new microwave radio relay system between New York and Boston, which Bell Laboratories are developing for the Bell System, giant lenses will shape and aim the wave energy as a searchlight aims a light beam.

This unique lens - an array of metal plates - receives divergent waves through a waveguide in the rear. As they pass between the metal plates their direction of motion is bent inward so that the energy travels out as a nearly parallel beam. At the next relay point a similar combination of lens and waveguide, working in reverse, funnels the energy back into a repeater for amplification and re-transmission.

A product of fundamental research on waveguides, metallic lenses were first developed by the Laboratories during the war to produce precise radio beams.

This "searchlight" is a milestone in many months of inquiry through the realms of physics, mathematics and electronics. But how to focus waves is only one of many problems that Bell Telephone Laboratories are working on to speed microwave transmission. The goal of this and all Bell Laboratories research is the same - to keep on making American telephone service better and better.

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Posted May 13, 2021

Bell Telephone Laboratories Infomercials