A 21-to-41-GHz High-Gain Low Noise Amplifier With Triple-Coupled Technique for Multiband Wireless Applications

This brief presents a wideband millimeter-wave (mm-Wave) low noise amplifier (LNA) with a triple-coupled technique for multiband wireless applications. To enlarge the gain and reduce the supply voltage, a modified cascode topology exploiting a triple-coupled transformer is developed. Thanks to the transformer, the transconductance of the common-gate (CG) transistor of the cascode topology is also effectively boosted, and hence the gain is further increased. Furthermore, high-order networks, which are realized by combinations of <inline-formula> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula>- and <italic>T/L</italic>-type structures or transformers, are employed to implement the input, inter-stage, and output impedance matchings. They significantly broaden the bandwidth of the circuit. The LNA is demonstrated using a commercial 65-nm CMOS process. The measurement results show that the circuit achieves a maximum gain of 28.5 dB and a 3-dB gain bandwidth of 20 GHz with 32-mW dc power consumption (<inline-formula> <tex-math notation="LaTeX">$P_{dc}$ </tex-math></inline-formula>). The measured noise figure (NF) and input 1-dB gain compression point (<inline-formula> <tex-math notation="LaTeX">$IP_{1dB}$ </tex-math></inline-formula>) are 2.7~3.2 dB and −24.6~−20.4 dBm, respectively, over the entire operating bandwidth.