A compact measurement set-up for envelope-tracking RF PAs with calibrated sensing of baseband V/I at the supply terminal

This paper presents a compact set-up to perform automated measurements of RF PAs under envelope-tracking (ET) operation. In addition to RF signal generation and acquisition, it allows calibrated measurements of the baseband voltage and current at the supply terminal with up to 40 MHz bandwidth, enabling instantaneous efficiency measurements. The presented set-up is used to extract two different shaping tables, and to test ET operation with a 5 MHz WCDMA and a 20 MHz LTE signals at 838 MHz. The used devices are an InGaP/Silicon RF power amplifier (PA) from Skyworks and a high voltage extra fast complementary bipolar (XFCB) power modulator (PM) from Analog Devices.