ANALYSES OF THE OPTIMAL POWER LOAD IMPEDANCES MEASURED IN MMIC AND HYBRID CONFIGURATION IN THE K-ALPHA BAND

This letter deals with the main different behaviors of the optimal pow er load impedances for two devices (PHEMT) studied in two configuratio ns (called ''probing'' or ''hybrid'') in power condition with an activ e load pull bench in Ka band (26-40 GHz), Contrary to what could;be ex pected, the difference is not only a phase shift, which is usually the case at lower frequencies, but a gap in phase and magnitude between t he optimal impedances, This behavior mill be presented, A linear elect rical simulation has been achieved in order to explain these behaviors .