Full-wave modal analysis of the rectangular waveguide grating

Dispersion characteristics of the rectangular waveguide grating for microwave amplifier applications are studied for the first time in the rigorous mathematical manner on the basis of the singular integral equation (SIE) method. In particular, the validity of the simplified approach is discussed by comparing the results obtained by both methods. Numerical results show that the dispersion curves obtained by the SIE method are in surprisingly good agreement with those obtained before. Additionally, it has been pointed out that there exists some regime where the differences between the SIE and simplified treatments become notable.