MT930H* active load pull module allows the control of ΓL as the ratio between the reflected- and forward-travelling waves at the output of the DUT . A generalized form of the formula can be written as ΓL = (a2/b2). The wave b2 is taken as the wave coming from the device, while a2 is the reflected wave seen by the device under test, coming either from a passive circuit, an active circuit or a combination of both for hybrid load pull.
Active injection load pull relies on external sources (with phase and amplitude control enabled) to inject a signal toward the DUT, thereby creating the appropriate a2 . Because a2 is no longer limited to a fraction of the original reflected signal, external amplifiers may be used to increase the amplitude of a2 so that ΓL can even achieve unity. To the contrary of harmonic passive tuners, a perfect isolation can be achieved between fundamental and harmonic load tuning, which is important when performances are mainly driven by the fundamental load. Finally, IVCAD algorithms enable a great tuning convergence and measurement speed.
*MT930H is an add-on module for MT930C