Safi, DjamschidDjamschidSafiBirtel, PhilipPhilipBirtelMeyne, SaschaSaschaMeyneJacob, ArneArneJacob2019-03-132019-03-132018-06International Journal of Microwave and Wireless Technologies 5-6 (10): 521-529 (2018-06)http://hdl.handle.net/11420/2151A selection of hybrid frequency-and time-domain approaches is evaluated with respect to their suitability for predicting the multi-tone behavior of a reference Ku-band helix traveling-wave tube. For this, a frequency-domain code is extended by a selection of frequency-dependent and frequency-independent envelope models and compared to a number of simulated and measured responses to two-tone signal excitation with varying frequency spacing. The selected envelope methods are investigated both in the hybrid approach and based on measured TWT characteristics. Output levels and classical multi-tone metrics, such as intermodulation products and phase transfer factors, are considered. By reducing a modulation scenario to a number of significant sequences, a comparison to full physics-based frequency-domain simulation is presented to show the potential of the proposed approach.en1759-079520185-6521529Journal Article10.1017/S1759078717001349Other