A Wideband Low Power Single-to-Differential GaAs LNA for mmWave Spectrum Monitoring Applications

The design of a low-power single-ended-to-differential low-noise amplifier (LNA) for spectrum monitoring applications is reported. The LNA is composed of a common source (CS) amplifier with inductive degeneration, followed by a common gate, common source (CGCS) active balun. The integrated 2 stage LNA have been designed at a central frequency of 25 GHz, with 10 GHz of bandwidth, using $\mathbf{0 . 1} \mu \mathrm{m}$ GaAs pseudomorphic high electron mobility transistors (pHEMT). The impact of the gate width and number of fingers on the performance is investigated. The simulations results show that the proposed 2 stage LNA achieves a 26 dB gain at 20 GHz and a noise figure of 0.86 dB, and remaining strong at 30 GHz with a gain of 21 dB and a noise figure of $\mathbf{1 . 2} \mathbf{~ d B}$. The power consumption of the LNA is 94 mW and has a compact chip size with an area of $1.5 \times 2.8 \mathrm{~mm}^{2}$.