A 3 to 5 GHz ultra-wideband low noise amplifier using InGaP/InGaAs enhancement-mode PHEMT technology

A In0.5Ga0.5p/InGaAa enhancement-mode (E-mode) pseudomorphic high electron mobility transistor (PHEMT), to demonstrate the performance of a 3-5 GHz ultra-wideband resistive shunt-feedback low noise amplifier (LNA). It was demonstrated that the resistive shunt-feedback achieves a wideband input matching, with a small noise figure (NF) degradation, as the Q-factor of the narrow band LNA input terminal was reduced. A low NF was demonstrated for the PHEMT LNA, as the In _0.5Ga _0.5P Schottky layer design provided low DX-center related defects and low oxidation rate with moisture. The measured results show a 15 dB gain from 3 to 5 GHz and the input/output losses are less than 10 dB. The minimum noise intercept point (IP3) of -8.5 dBm and an output third-order intercept point (OIP3) of 9.7 dBm were also obtained.