Low frequency noise measurements — A technology benchmark with target on oscillator applications

This paper presents low frequency noise (LFN) measurements of some commonly used microwave transistor technologies, e.g., GaAs-InGaP HBT, GaAs pHEMT, and GaN HEMT. It investigates how the flicker noise scales with current and voltage in the different technologies. The target application is low-phase noise oscillators. From this perspective, low-frequency noise at given frequency normalized to DC power is used as benchmark parameter. A comparison between different measurement set-ups is also included. The problem of measuring low-frequency noise at high drain voltages and currents is considered. It is found that the flicker noise of GaN HEMT technology is in about the same level as of GaAs pHEMT, but when normalized with the DC power, GaN HEMT offers a better performance. For this reason, GaN HEMT is considered to have better potential in oscillator applications. Concerning InGaP HBT, when measured at 10 kHz it provides better performance in term of both absolute noise level and normalized values. Higher frequencies are in favor for GaN HEMT technology.