Restrictions in Using Large Signal and Small Signal Models of FET Transistors

A frequency doubler from 8.5 to 17 GHz was used to study reliability and accuracy of large signal Curtis Cubic model of HEMT transistor. Excelics EPA018A-70 was used for the tests. Two large signal designs and realizations for working points in class B and open state (near I_dss) were made. Another design based on measured small signal s-parameters only was done for comparison, too. AWR Microwave Office was used for simulations. All designs were realized and measured. Significant discrepancies between simulated and measured parameters for Curtis Cubic model operated in class B were observed.