Millimeter waves and Gaussian beams in modern communication

Summary form only given. Remarkable pioneering experimental work in millimeter-wave techniques was done by Sir Jagadis Chandra Bose in Calcutta in the 1890s. He developed and used many of the microwave and millimeter wave quasi-optical components that are in use today, including waveguides, horn antennas, dielectric lenses, prisms and wave polarizers, and made the first experimental demonstration of wireless communication at a distance. Bose's experiments were carried out at wavelengths from 2.5 cm down to 5 mm. Curiously, interest in millimeter waves did not develop further until about the end of World War II when radar technology spurred interest in millimeter waves because of the obvious advantage of achieving sharp radiation beams using antennas of relatively small aperture. The 1960s witnessed much progress in millimeter wave technology with the development of Gunn and IMPATT diode oscillators. New uses of this technology in the fields of terrestrial and satellite communication emerged.