Wide-band Hybrid Single-Ended and Differential LNA Designs Using GaAs pHEMTs and Comparison with In-house InP pHEMT Based LNA Design

This work presents single-ended and differential MIC LNA designs to meet the requirements for the Square Kilometre Array (SKA) at the low frequency band ranging from 0.3-1.0 GHz Hall (2004). A series of single-ended MIC LNAs on 50Ω system, with various topologies have been designed to study their NF, gain, SWR, power and stability characteristics. Subsequently, differential LNAs using commercial GaAs pHEMTs were designed and optimised for the Orthogonal Ring Antenna (ORA); the proposed antennas for the phased array of the SKA. Test structures have been developed to measure the four-port differential LNAs using two-port Vector Network Analyser (VNA) and Noise Figure Analyser (NFA). The measurement techniques were presented in Abidi & Leete (1999); Belostotski & Haslett (2008). The above results were then compared with the low-power double stage differential to single-ended MIC LNA design Arshad et al. (2009) developed using an in-house fabricated novel InGaAs/InAlAs/InP pHEMTs Bouloukou et al. (2006).