Characterization of MMIC (Monolithic Microwave Integrated Circuit) Devices for Active Array Antennas,

It has become evident from NASAs active array technology development activities that more attention to the characterization of MMIC devices is needed. Having been fabricated using lithographic techniques, the MMIC has some inherently reproducible RF characteristics. NASA is currently sponsoring studies by the University of Illinois to investigate certain aspects of MMIC interconnectivity. These investigations are expected to contribute to a data base that will lead to providing for reproducible test results by the user as well as the manufacturer. Some considerations are proposed that lead to preserving the inherently reproducible characteristics of the MMIC. It is highlighted that at frequencies greater than 20 GHz, the transition from the MMIC device to other transmission media must be an accurate RF match. It is proposed that the RF match is sufficiently critical to include the transition as part of the delivered MMIC package. The model for analyzing several transitions will be presented. This model consists of a succesion of abrupt discontinuities in printed circuit transmission lines. The analysis of these discontinuities is achieved to generate the generalized S-parameters of the individual discontinuities. Preliminary results achieved with this method are presented.