Objective quantification of mode competition in THz BWO optimization

The corrugated rectangular waveguide slow-wave structure (CRWSWS) terahertz (THz) backward wave oscillator (BWO) is suitable for many applications because of its compactness and portability. An analytical model is proposed for calculating the cold and hot parameters of a CRWSWS THz BWO. Two forms of mode competition are quantified using the analytical model. The quantifications are used as objectives when optimizing the CRWSWS THz BWO. The optimization is performed based on the analytical model and a local search algorithm. The optimization results are verified using CST Microwave Studio and Particle Studio. The influence of one of the quantifications on the convergence of the optimization algorithm is also investigated.