Philip Hagar Smith

Smith was born on April 29, 1905, in Lexington, Massachusetts. During his schooling in Tuft, he started working with amateur radio (1ANB), and he was a musician as well. He received the BSEE certification from Tuft University.

He went to Bell Labs in 1928. He started on works on a short wave antenna system for the connection infrastructure with Europe and South America. But transverse electromagnetic waves and the adaptation to antennas particularly interested him. At this time, there were still no network analyzers, and one had to use a thermal bridge and a micro voltmeter to obtain the minima and maxima along a line. On the basis of the telegraph equations, he simplified the adjustment procedure with the help of a rectangular diagram. After various improvements, he invented the modern (round) Smith Chart in 1937. The article appeared in "Electronics Magazine" in 1939. He also presented admittance circles in 1944.

Briefly before America entered World War Two, he was assigned to manufacture antennas and coaxial cable at the radar facility SCR-268. He owned a patent on an optimized coaxial cable with maximum power transmission. At that time, Smith said, this was one of the simplest patents, the secret lay in the number 1.65. Likewise, he held a patent for adjustable tuners.

After World War Two, Smith worked for Western Electric Radio, whereupon weapon radar systems became the focus of his work. In 1970, he went into retirement and left Bell Labs. On August 29, 1987, he died at 82.