The traditional application areas of millimeter-wave radiation are in the fields of radio-astronomy, remote sensing, plasma diagnostics, and imaging through dust and fog in military situations. It is the purpose of my Presidential Young Investigator research effort to develop low-cost millimeter-wave integrated antennas, receivers and transmitting systems. This research will open the doors to many civilian application areas such as collision avoidance systems, landing systems, small portable communication systems, etc. Providing high performance and less expensive receivers will also enhance the radio-astronomical and remote- sensing application areas. The proposed research plan is as follows: l) Develop 100-500 GHz low-noise planar receivers using high- efficiency integrated horn antennas and Schottky- diodes. Also, use newly-developed 90 GHz low-noise amplifiers with a planar antenna and a CPW (coplanar-waveguide) matching network to result in a low-noise receiver with gain. 2) Generate efficiently 100-1000 GHz radiation from solid-state sources such as planar varactors and transistors coupled to antennas. Different circuit configurations that allow phase-locking and frequency sweeping will be investigated. The output can be used as local oscillator in a receiver set-up or as a transmitter for short-range radar applications.