Impact of the duty cycle on the pulse-to-pulse stability of a GaN power amplifier

Abstract : This paper presents a heterodyne measurement system of the pulse-to-pulse (P2P) stability and its application to time-domain measurements of a GaN HEMT microwave power amplifier. Envelope and P2P stability measurements are performed for an irregular RF pulse train which integrates a long silence between each pulse sequence. This paper is focused on the impact of RF pulse width and duty cycle on each pulse sequence. Coherent measurements of time-domain envelope and P2P stability are performed on a 10W S-band GaN power amplifier. Indeed, one aim of this work is to illustrate the great impact of temperature and trapping effects on the envelope response and P2P stability of GaN power amplifiers.