Low Noise Design Strategies for Mixers and Amplifiers

Inhalt:
The paper presents analytical formulas for the phase-noise in microwave amplifiers and mixers at low frequencies, which have been verified using circuit CAD tools. These expressions are used to improve the RF and 1/f noise performance of bipolar and FET circuits. It has been found that using circuit design approaches for wideband circuit operation improves the phase-noise performance. Wideband operation using series/shunt peaking and current compensation techniques has been studied resulting in an overall noise figure improvement by up to 7 dB at all frequencies in case of a HEMT Gilbert cell mixer circuit.