Theoretical Analysis of a Low Dispersion SiGe LNA for Ultra-Wideband Applications

We demonstrate a low dc power consumption SiGe heterojunction bipolar transistor (HBT) low noise amplifier (LNA) for ultra-wideband (UWB) applications covering the 0.5GHz to 10GHz band. Using theoretical analysis, the dominant design factor for low group delay variation is identified and applied to UWB LNA design. The implemented SiGe LNA achieves a gain of 13dB, a minimum noise figure of 3.3dB, and an IIP3 of -7.5dBm between 0.5GHz and 10GHz, while consuming a dc power of only 9.6mW. This SiGe UWB LNA exhibits less than 22ps of uniform group delay variation over the entire band. To the best of the authors' knowledge, this is the first attempt to analyze the effects of group delay variation on the operation of wideband LNAs

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