AM-PM characteristics of low noise block converters

Low noise block converter is one of the key nonlinear devices for spectrum sharing between IMT-A and FSS on 3GHz band based on the result of World Radiocommunication Conference 07. We measured AM-PM characteristics of several off-the-shelf Low Noise Block converters (LNBs) and compare the characteristics with conventional nonlinear device models. On measuring AM-PM characteristics of LNBs, LNBs have frequency conversion function and their local oscillator may not be stable in a long period for the measurement. Then we propose a method for AM-PM measurement which eases required frequency tuning accuracy of the measurement system. The results show that conventional models fit well on the whole, however there are rooms to be improved in their accuracy and usability. Then, in this paper, we also propose a novel AM-PM model based on the concept of the Rapp´s AM-AM model.