每年出版 12 期
ISSN 打印: 0040-2508
ISSN 在线: 1943-6009
Indexed in
WAVE TRANSMISSION THROUGH A WAVEGUIDE SECTION WITH RANDOMLY CORRUGATED WALLS: A DUAL NATURE OF THE LOCALIZATION
摘要
A theory is developed of wave propagation through waveguide structures which include a finite-length section with randomly corrugated lateral boundaries. It is shown that the principal role in the waveguide state formation is played by the gradient mechanism of scattering where the roughness sharpness is determinative instead of their amplitude. The rough section of the waveguide plays a role of an effective modulated potential barrier whose width coincides with the section length while the height is dependent on the mean sharpness of the waveguide boundary irregularities. Structures of the kind support two types of the wave localization. The first of these consists in a sequential cutoff of the waveguide modes as the irregularity sharpness is increased. This effect results in thinning out the waveguide spectrum such that with sufficiently sharp irregularities the structure operates as an evanescent-mode waveguide. The second mechanism is the conventional Anderson localization associated with multiple scattering of the waveguide modes by random fluctuations of the effective potential. An abrupt increase (up to 100 %) of the waveguide conductance as the waveguide passes to operate in an effectively single-mode regime due to the gradient mode renormalization associated with disappearance in this case of the inter-mode scattering channel.