TRANSIENT BEHAVIOR OF MICROWAVE NETWORKS

The study was performed as part of a program to obtain evaluation techniques for broadband components and microwave systems used in radar. The work reported falls into three categories: (1) Development of analytical and experimental techniques for measuring the frequency-domain characteristics of a microwave network by the Fourier transform of its transient response: (2) Investigation of the TEM-mode network characteristics which influence system performance: (3) Analysis of the theoretical and experimental problems involved in the design and construction of signal sources for generation of coherent microwave energy. Analytical expressions are presented for translation errors such as aliasing, truncation, time-jitter and noise. Results obtained from measurements on typical time-invariant linear networks with the experimental system for translation between domains exhibited an overall discrepancy of 0.5 dB and 5 degrees; with greater experimental care absolute errors approaching plus or minus 0.1 dB and plus or minus 1 degree appear possible. Time-domain distortion analysis techniques are compared to the conventional paired-echo approach, and several time-domain approximation techniques are analyzed. Generation techniques are reviewed and several series and parallel pulse-forming networks are described in detail. Generation of coherent energy by harmonic filtering and upconverting is also discussed. (Author)