Improvement of Up-converters linearity for Ka-band operation

Abstract

The application of a digital predistorter to the linearisation of a Ka-band mixer is presented herein. The general objective in the TX design is to get the best trade-off between linearity and costs. This require the most of the simplicity and possibly to take advantage from already existing device without perturbing its other functionalities. After a presentation of the problem and its constraints, we present the digital predistorter, which has been tested and debugged by means of IEEE-488 bus (GPIB) controllable instrumentation (EMA, electronic measuring automation) in order to finally consider its implementation on a fast newgeneration FPGA device. Results show an increment of the linear zone in the up-converter AM-AM curve, of about 15 dB.