Method of moments/transmission line modeling for plasma excitation single-layer slotted waveguide arrays with complicated outer baffles

Single-layer slotted waveguide arrays (SWA) are promising candidates for generating a large area plasma. The analysis for one slot in a SWA with a complex external structure with the assumption of two dimensional periodicity in the external region is demonstrated with a simplified model. This model is analogous to that for a dual-polarized waveguide slot antenna (Josefsson, L. et al., IEEE AP-S Symp., p.625-8, 1992). In the proposed analysis, the whole structure is decomposed into those separated at the structural discontinuities, which are analyzed separately for the scattering matrix by using the method of moments (MoM). Then, the whole system is expressed as a cascade of scattering matrices (S-matrices) in the transmission line modeling (TLM) method; it may be named MoM/TLM analysis. The advantage of this method is that the condition number in the matrices remains small in comparison to that for a whole structure solved at once. For confirmation of the analysis, a simplified model is adopted. The calculated transmission coefficient inside the waveguide is compared with that by HFSS, and good agreement is observed.