An Unequally Spaced Multi-Tone Passive Load-Pull (USMT-PLP) to simultaneously characterize Linearity and Efficiency of RF Power Devices

This paper presents an experimental set-up to evaluate the in-band signal-to-noise radio degradation, through load-pull large signal measurement as proposed in [1].The Unequally Spaced Multi-Tone (UMST) is a tailored stimulus signal that presents flexible characteristics in terms of peak to average power ratio (PAPR), envelope probability density function (PDF), and radio-frequency (RF) bandwidth.The purpose of this measurement is to fully characterize third order intermodulation (IM3) products without involving any overlap between the different IM3 tones and the generated pilot tones.The automated test bench offers new perspectives for power amplifier (PA) designers, to design the output matching networks for achieving the best trade-off between linearity and efficiency. This is achieved by plotting simultaneously the impedance contours for a predetermined critera like the output power, the power added efficiency (PAE) or the carrier to intermodulation ratio (C/IM3). The USMT measurement can be also useful to perform nonlinearity measurement.