A novel computerized multiharmonic active load-pull system for the optimization of high efficiency operating classes in power transistors

Abstract

A fully automated multiharmonic load-pull system allowing accurate measurement and control of the fiist three harmonic load terminations of RF and microwave transistors is presented in this paper.The technical originality of the proposed system lies in that the first. second and third harmonic load terminations can be independently and automatically monitod and fixed while varying the input power driving the transistor at the fundamental frequency.Appropriate hardware and software allow fast and automatic plots of power / efficiency performances of DUTs versus input power for different harmonic loadings.To demonstrate an attractive application of the system, measurements of a 1800 Fm gate periphery MESFET at 1.8GHz for mobile communication applications are presented.Both suitable harmonic load terminations and nonappropriate ones yielding respectively optimum and poor power added efficiency are given.

Nonlinear approaches to the design of microwave power amplifiers

“…Harmonic load-pull techniques have been proposed [27,28], thus allowing the investigation of the effects of the harmonic load terminations that have a relevant role for high-efficiency performances. If such load-pull techniques are matched to a harmonic-tuning design approach, an experimental strategy can be implemented in order to effectively design a highefficiency PA [29].…”

“…The harmonic-tuning strategies, except for the Class F design, often appeared to be derived from a merely experimental approach [22,27] or to be the result of more or less justified choices [23][24][25], rather than being based on fully understood physical mechanisms.…”

Automated characterization of HF power transistors by source-pull and multiharmonic load-pull measurements based on six-port techniques

“…Appropriate calibration 0018-9480/98$10.00 © 1998 IEEE methods assure vector corrected measurements at the device's input and output ports. The use of an ANA for multiharmonic measurements requires a frequency converter either in form of an additional device [9] or built-in [4], [17] in order to enable the ANA to measure at harmonic frequencies. In case of a DSPNA which does not need a reference signal, frequency selection can be carried out by switched filters [12] or tunable filters.…”

Simple technique for measuring source reflection coefficient while characterizing active devices

“…1 shows a load-source pull test set, which became common over the last decade for nonlinear characterization [1]- [6]. Two mismatch boxes set the source and load conditions, respectively at the input and output ports; those systems can be passive mechanical tuners or the more recent active tuners [1]. An automatic vector network analyzer (VNA) and two reflectometers measure the waves at the reference planes of the device-under-test (DUT).…”