Prof Hidetsugu Yagi ? a true legend

Prof Hidetsugu Yagi

Prof Hidetsugu Yagi

In every era in almost every category one will find geniuses, like the Mozart?s of classical music, the Einstein?s of science and the Michelangelo?s of art. In the last 100 years there have been a few remarkable people whose contributions laid the foundations that would shape the antenna industry as we know it today. One of these antenna legends is a Japanese professor, Hidetsugu Yagi, well known as the father of the Yagi antenna.

I recently discovered a re-publication paying homage to a paper published by Mr Yagi in 1928 titled, ?BEAM TRANSMISSION OF ULTRA SHORT WAVES?. [Reference: James. E. Brittain, ?Yagi on a Microwave Communication System?, PROCEEDINGS OF THE IEEE. VOL. 72, NO. 5, M A Y 1984]. It was fascinating to see the discoveries they made almost a century ago long before the existence of transistors. Prof Yagi and his student Shintaro Uda (hence the name ?Yagi-Uda antenna?) discovered that positioning an element having a slightly higher natural frequency next to a single driven element acts like a director shaping the radiation pattern to be more directive where a slightly lower resonant frequency element acts like a reflector. Up until then most experiments had to be done at > 100 cm wavelengths (lower than 300 MHz) simply because they couldn?t produce stable oscillations at higher frequencies. A quote from the same paper: ?Mr. K. Okabe, assistant professor at the Tohoku Imperial University has succeeded in generating exceedingly short sustained waves by introducing certain modifications in the so-called magnetron.? Could this be the first microwave signal generator?

These guys didn?t have the luxury of ordering components and connectors from a catalogue, design and build something and plug it in to a signal generator, simply turning the knob to the preferred frequency. They probably had to start preparing for a measurement by making the cable!

As Isaac Newton once famously remarked in a letter to his rival Robert Hooke in 1676:

“If I have seen a little further it is by standing on the shoulders of Giants.”

How many things do we – as ?modern? antenna engineers – take for granted, when infact we are truly standing on the shoulders of Giants?

Author: Robert Kellerman

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