A 2–20-GHz Ultrawideband High-Gain Low-Noise Amplifier With Enhanced Stability

This letter discusses a high-gain low-noise amplifier (LNA) operating in the 2–20-GHz range, employing the 90-nm GaAs E-mode pseudomorphic high-electron-mobility-transistor (pHEMT) process for enhanced stability. The proposed modified cascode topology integrates a low-pass matching network, featuring a series inductor and a parallel capacitor between the common-source (CS) and common-gate (CG) transistors of the cascode cell, enhancing stability with minimal noise and gain degradation. Measurements indicate that the proposed LNA achieves a gain of 25 dB, with the input–output return loss better than 10 dB and an NF below 1.5 dB. Further testing demonstrates that the proposed LNA does not exhibit any instabilities over the entire frequency band from dc to 40 GHz.