Title :
A predictive model describing the upconversion of 1/f noise into AM sideband noise in HBTs
Author :
Pehlke, D.R. ; Sailer, A. ; Ho, W.-J. ; Higgins, J.A. ; Smith, H. ; Hebert, J. ; Vineyard, M.
Author_Institution :
Rockwell Inst. Sci. Center, Thousand Oaks, CA, USA
Abstract :
An analysis of AM noise in AlGaAs-GaAs HBT amplifiers is presented. A predictive model is introduced which allows calculation of AM noise sideband power alongside carrier signals in HBT amplifers as a result of the upconversion of low frequency noise. These sidebands are an unavoidable result of the nonlinear components in microwave oscillators and power amplifiers which causes upconversion of intrinsic low frequency 1/f noise into amplitude modulated (AM) and phase modulated (PM) sidebands about the carrier. AM and PM sidebands degrade the spectral purity of the carrier which ultimately limits system performance in communication systems. Many works have described the upconversion process in microwave oscillators with its dominant phase noise, but less attention has been paid to the AM noise of power amplifiers. This work presents the theory of such noise in AlGaAs-GaAs HBT amplification and details a predictive model that allows calculation of AM noise sidebands for any HBT device.
Keywords :
1/f noise; III-V semiconductors; aluminium compounds; amplitude modulation; circuit noise; equivalent circuits; gallium arsenide; heterojunction bipolar transistors; microwave bipolar transistors; microwave power amplifiers; microwave power transistors; millimetre wave bipolar transistors; millimetre wave power amplifiers; millimetre wave power transistors; power bipolar transistors; semiconductor device models; semiconductor device noise; 1/f noise upconversion; 170 GHz; 40 GHz; AM noise analysis; AM sideband noise; AlGaAs-GaAs; AlGaAs-GaAs HBT amplifiers; HBT amplification; low frequency noise; power amplifiers; predictive model; Frequency; Heterojunction bipolar transistors; Low-frequency noise; Low-noise amplifiers; Microwave amplifiers; Microwave oscillators; Noise level; Phase modulation; Phase noise; Predictive models;
Conference_Titel :
Device Research Conference, 1995. Digest. 1995 53rd Annual
Conference_Location :
Charlottesville, VA, USA
Print_ISBN :
0-7803-2788-8
DOI :
10.1109/DRC.1995.496286
