Design of low noise amplifiers for the DRAO synthesis telescope.

摘要

This thesis documents the design of low noise amplifiers (LNAs) with coaxial connectors and probe LNAs for the Dominion Radio Astrophysical Observatory (DRAO) Synthesis radio telescope. Both designs use Agilent ATF-34143 pseudomorphic high electron mobility transistors (pHEMTs). The design process included measurement of the ATF-34143's scattering parameters (S-parameters) for circuit and noise modelling. ATF-34143 S-parameters were obtained from 0.5-10 GHz and a LNA with coaxial connectors and 30 K noise temperature was designed and constructed. The LNA has a noise performance 5 K better than the noise performance of the LNAs currently operating on the Synthesis Telescope. The probe LNA design is a fairly new and promising concept, integrating the waveguide probe directly into the circuit board and eliminating coaxial connection losses. Currently, the probe LNA has the same noise performance as the LNA with coaxial connectors when placed in a waveguide.