MMIC antenna technology development in the 30/20 gigahertz band

This paper presents a progress summary of NASA's efforts in developing 20 and 30 GHz GaAs MMIC devices and an advanced satellite communications antenna system using these devices. In the interest of preserving resources such as frequency spectrum and orbital space the antenna system is being developed with multiple fixed spot beams and multiple scanning spot beams. NASA set high goals for the MMIC development to push GaAs technology. These goals and the main features of the MMIC devices are discussed. Some packaging and characterization considerations are also discussed. The 20 GHz transmit antenna and 30 GHz receive antenna are being developed separately. The approach selected is to perform contractual configuration studies, purchase a 20-GHz experimental antenna system (EAS) and perform in-house evaluation. The features and key specifications of the EAS are discussed. Additional supporting technologies such as effects of coupling on modest sized arrays, MMIC matching techniques, in-house analytical capability, wideband and dual frequency microstrip patch array development, and MMIC packaging techniques are described. Some plans for future work are also discussed.