Radio transmission in the millimeter-wave region

The utilization of the millimeter-wave region for radio transmission applications has a number of advantages compared to an employment of the VHF and UHF frequency bands or the use of directional radio technology. The advantages are related to a reduced antenna diameter in case of an equal antenna aperture angle, an enhanced intermediate frequency bandwidth for the transmission of data at high bit rates, improved safety from interception, and interference-free operation in short-range communication. However, a number of difficulties have to be overcome in connection with the utilization of the considered advantages. Rapid advances in semiconductor and component technology have now provided the required basis for satisfying more exacting requirements concerning frequency stability. Attention is given to three main areas of application for millimeter-wave transmission technology, taking into account satellite communication, Low Probability of Intercept (LPI) communication, and telephone, video, and data transmissions at high bit rates.