Greenleaf Whittier Pickard (February 14, 1877 – January 8, 1956) was an American inventor and electrical engineer best known for his contributions to early radio technology. He was a key figure in the development of the crystal detector (commonly known as the "cat's whisker" detector), which served as the first widely used device for rectifying radio signals and enabled the reception of amplitude modulation (AM) broadcasts.
Born in Portland, Maine, Pickard was a grandnephew of the poet John Greenleaf Whittier. He attended the Lawrence Scientific School at Harvard University but left before graduating to pursue work in the nascent field of wireless telegraphy.
In 1906, while working for the American Wireless Telephone and Telegraph Company, Pickard discovered that the junction between a fine metallic wire (the "cat's whisker") and certain crystalline minerals (such as silicon, galena, or iron pyrite) could rectify high-frequency alternating currents, allowing for the detection of radio signals. He was granted U.S. Patent 836,531 for this "Means for Receiving Intelligence Communicated by Electric Waves" in 1906. This invention provided a reliable, inexpensive, and user-adjustable alternative to the coherer and the electrolytic detector, significantly advancing the practicality of radio receivers.
Pickard held over 30 patents related to radio and antenna systems. He conducted extensive research on loop antennas, direction finding, and the effects of the ionosphere on radio wave propagation. He was a founder of the Wireless Specialty Apparatus Company (WSA) and later served as a consultant for the Radio Corporation of America (RCA).
He was a Fellow of the Institute of Radio Engineers (IRE) and served as its president in 1913. In 1926, he was awarded the IRE Medal of Honor "for his contributions to crystal detectors, loop antennas, and direction-finding systems." In 1984, he was inducted into the National Inventors Hall of Fame.
