A 23.2-40.3 GHz Low-Noise Amplifier with Transformer-Based T-Type Topology

This paper presents a low-noise amplifier (LNA) circuit with a 3-dB bandwidth (3-dB BW) gain, utilizing a T-matching network in a cascode structure, designed for the frequency range of 23.2-40.3 GHz. Analysis of the T-matching network for interstage matching shows that it can generate two peak gain points at low and high frequencies, effectively enabling interstage bandwidth extension. Recognizing the critical importance of minimizing noise figure (NF) in the first stage, a cascode structure with transformer coupling and the T-matching network is employed to enhance transconductance while mitigating noise. To further reduce noise contributions from the last two stages and ensure proper input-output impedance matching, the same T-matching network and a cascode structure is adopted in the final stages. The proposed LNA achieves a 3-dB bandwidth of 23.2-40.3 GHz, with a peak gain of 24.8 dB at 33.8 GHz. The minimum noise figure is 2.49 dB at 25.42 GHz, and the circuit consumes 24 mW of DC power.