A Fault-Tolerant Wideband Amplifier Based on Distributed Amplification Topology

The failure of the transistor could make an amplifier useless, bringing the wireless system to a sudden halt. Therefore, an amplifier which can handle this type of fault without introducing additional components is highly demanded in industrial applications. For this purpose, a distributed amplification topology is proposed in this paper. The robustness of the proposed structure was theoretically verified by analyzing the ideal models of the amplifier under normal and failed modes. The possibility for further performance enhancement using tunable components is also theoretically investigated. For validation, a wideband amplifier which covers a bandwidth from 0.75 to 2.4 GHz is designed, fabricated, and measured. To verify the robustness, the cases with one and two field effect transistors (FETs) failed are evaluated. For the case with one failed FET, the implemented amplifier maintained a comparable performance over the operating frequency band. For the case with two failed FETs, the same bandwidth can be maintained with the unavoidable minor degradation in gain and gain flatness. The unique fault-tolerant property of the proposed topology is demonstrated. As a beneficial supplement to the proposed fault-tolerant architecture, the proposed optimization approach is applied to achieve a better tradeoff among return loss, gain, and gain flatness.