Microwave Limiting Amplifier

The X-band limiting amplifier is a part of the front-end for X band receiver. In this thesis, a X-band limiting amplifier is designed. The purpose is to compress the dynamic range of input signal from 40dB to 5dB.Microwave limiting amplifier is widely used in electronic detecting and interfering radar system. So design a high performance limiting amplifier is a very important research direction.A X band microwave limiting amplifier is realized according to the theories of the output power saturation characteristics of HEMT. This dissertation mainly described the theory and design methods of limiting amplifier. At first, we review the basic theories and design methods of amplifier. After that, the essential theories and realization methods are discussed. The proper designing scheme is selected. And then, we analyze the nonlinear properties of limiting amplifier. Due to the typical nonlinear properties of limiting amplifier, we studied the method of academic analysis for microwave nonlinear circuit and the nonlinear circuit model of transistor in detail. The nonlinear properties of transistor in large signal condition are simulated by ADS (Advanced Design System) using the nonlinear model of transistor and Harmonic balance analysis technique.The module design method is adopted in this dissertation. For the system application, we cascade multi-module to satisfy the system's demands. The measured results of fabricated limiting amplifier are in agreement with EDA simulation results. The experimental results indicate that the X-band limiting amplifier can satisfy performance demands of X band receiver.