Sir J.C. Bose and millimeter waves

The World's first wireless communication system for remote control of gun firing together with ringing a bell, was developed by Sir J.C. Bose during the last 3 years of 1894. The system operated over a distance of 23 m through two intervening walls, using a millimeter wave of 5 mm wavelength, corresponding to the frequency of 60 GHz. The reason for the choice of millimeter wave by Sir J.C. Bose was primarily due to the advantage of studies of quasioptical properties of the radio waves within his laboratory of limited size, that was available to him at the Presidency College. However, the components and systems developed by Sir J.C. Bose, initially at millimeter wave and subsequently at microwave, were outstanding discoveries made more than 100 years ago, in Calcutta, India, most of which are now being utilised, in a modernised form for Earth/space links and remote sensing. The paper focuses on the significant contributions of Sir J.C. Bose at microwaves and millimeter waves and their current applications.