Conception d'un amplificateur faible bruit LNA à base d'un transistor à effet de champ à hétérojonction pHEMT

Abstract

In the last few years, a successful progress has been achieved in the field of designing and implementing MMICs employing compound semiconductors. One of the most exciting applications of this technology is the Square Kilometer Array (SKA) radio telescope. The main objective of this work is the design of an MMIC InP-pHEMT broadband LNA in the L- band (0.4-2 GHz) with the lowest possible noise figure and as flat gain response as possible. Accurate linear small-signal and nonlinear large-signal models have been extracted for our fabricated high breakdown 1 μm InGaAs-InAlAs-InP pHEMT based on practical on-wafer device measurements. In this work, we discuss the design of two low noise amplifiers (LNA) based on 1 um gate-length pHEMT InP transistors using two topologies. Designed for radio astronomy applications, the first is a cascode circuit with a maximum gain of 15 dB and noise figure of 0.61 dB, while the second is a 2-stage cascaded amplifier with 33dB of gain and 0.63 dB of noise figure. The two amplifiers exhibit an output -1 dB compression point of -13 dBm and 2 dBm respectively, and a third order input intercept point of -20 dBm and -23 dBm, respectively. Keywords: HEMT amplifier, Modeling of microwave; Analog electronic circuits