A 1–15-GHz Low-Power Self-Stabilizing DC-Capacitorless LNA With Tri-Path Dual-Coupling

This article presents an ultrawideband (UWB) low-noise amplifier (LNA) designed to extend bandwidth and enhance radio frequency (RF) performance under stringent low-power constraints. A self-stabilizing dc-capacitorless architecture is proposed. By eliminating the conventional dc-blocking capacitor, the amplifier achieves significant improvements in gain and noise figure (NF). A self-stabilizing bias network (SSBN) is incorporated to stabilize the bias voltage and compensate for bias point drift caused by the absence of the dc-blocking capacitor. Furthermore, multiple-resistor feedback and tri-path dual-coupling (TPDC) technique are used to greatly enhance the bandwidth. TPDC is first proposed in this letter to our knowledge. These techniques are adopted in a two-stage monolithic microwave integrated circuit (MMIC) LNA, which is fabricated in a 0.25-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula>m GaAs pseudomorphic high-electron-mobility transistor (pHEMT) process. The measured results show a peak gain of 17.7 dB, 1.3-dB minimum NF, and a 3-dB bandwidth of 1–15 GHz with a dc power consumption of only 39.6 mW. The fabricated LNA, including the testing pads, has a chip size of only 0.92 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.