Safi, DjamschidDjamschidSafiBirtel, PhilipPhilipBirtelMeyne, SaschaSaschaMeyneJacob, ArneArneJacob2019-11-262019-11-262017-12-19European Microwave Week, EuMW, EuMC 2017: 852-855 (2017-12-19)http://hdl.handle.net/11420/3886A selection of frequency dependent and frequency independent envelope models is evaluated with respect to their suitability of predicting the multi-tone behavior of a reference Ku-band helix traveling-wave tube. A comparison of simulated and measured responses to two-tone signal excitation with varying frequency spacing is presented. The output power levels and classical multi-tone metrics, such as intermodulation products and phase transfer factors are considered.enAllgemeines, WissenschaftConference Paper10.23919/EuMC.2017.8230978Other