A Technique to Extend the Bandwidth of an RF Power Amplifier Test Bed

In this paper, a method for increasing the bandwidth of a test bed for dynamic characterization of power amplifiers (PAs) is described. The technique is readily implemented using commercially available instruments, which makes it suitable for, e.g., production testing. The bandwidth extension technique is combined with coherent averaging of the measurements in order to simultaneously increase the bandwidth and dynamic range of the test bed. The errors in the obtained wideband signal are also estimated. The method is evaluated experimentally on a base station PA for the third-generation wideband code division multiple access system and on a Doherty amplifier. A tenfold increase in bandwidth to a total of 144 MHz and a more than 10-dB increase in dynamic range to 78 dB were obtained in practice. In addition, the obtained wideband signal is used for behavioral amplifier modeling.