Design and Analysis of 3–12 GHz UWB Flat Gain LNA in 0.15 µm GaAs pHEMT Technology

This paper presents the design and implementation of an ultra-wideband (UWB) and flat gain low noise amplifier (LNA) using 0.15 µm GaAs pHEMT technology, specifically tailored for applications that benefit from multi-band capability, such as satellite communication. The designed LNA consists of three stages: Two stages are cascoded using source degeneration with a resistor for low noise and high linearity, and the third cascaded stage is utilized for high gain. The designed UWB LNA exhibits a measured gain of 17.4 ± 1 dB between 312 and GHz and a 3 dB bandwidth of 12.4 GHz (1.6–14 GHz). It achieves a noise figure (NF) of 2.5–4.3 dB and an output P1dB of 15 dBm. The chip size is 3×1mm2, and it operates without the need for any external components. When compared to LNAs in the literature, the proposed design stands out for its flat gain in the specified frequency band, making the LNA particularly attractive for volume-limited and power-constrained applications.