TERAHERTZ GaAs DEVICES AND CIRCUITS FOR HETERODYNE RECEIVER APPLICATIONS

GaAs Schottky barrier diodes are used in heterodyne receiver applications to frequencies as high as 4,000 GHz. The primary application that has driven this technology has been radio astronomy. However, other applications are now also very important, particularly studies of the constituents of the Earth’s atmosphere. This paper presents a summary of this increasingly important technology. The requirements that the diodes must meet and the benefits of GaAs Schottky devices are discussed. The optimization of the diodes for frequency mixing and multiplication throughout the frequency range of interest is overviewed. The analysis of terahertz frequency electronic transport in the diodes is then briefly considered with an emphasis on numerical modeling techniques. The typical circuit designs and the efficient coupling of energy are considered, and the state-of-the-art systems are reviewed. Finally, ongoing and future research topics are discussed. It is concluded that although this technology is quite well developed, much remains to be done, particularly in the areas of combining accurate circuit and device simulations for optimization and design purposes and the development of lower cost systems.