Waveguiding and anomalous properties of a knife-type periodic strip grating

The existence criteria of waveguiding properties of a periodic plate grating for different waveguiding modes are demonstrated. Dispersion relations are obtained and pass and stop bands are determined. The asymptotic form of dispersion relations at the infinite increase of a grating elements sizes and the wave number decrease were derived. The anomalous oscillations near the periodic plate gratings are investigated. It is proved, that such oscillations always exist. The influence of the geometric characteristics and knife-type grating mode on the oscillation frequency, number and type of waveguiding and cycle modes was investigated. Waveguiding and cycle modes of oscillations are classified by groups of allowed symmetries. Comparison is made with known experimental and numerical results.