Reflection and Scattering of Electromagnetic Waves in Spatial Grids Consisting of Multiple Lossy Waveguides

Yasumitsu Miyazaki
2009 PIERS Online  
Medical diagnosis technologies using X-ray and optical wave transmitted tomography have been rapidly developed with computer processing. X-ray and optical transmitted field characteristics in CT, that depend on biomedical absorption due to bio-molecules and atoms, yield biomedical information of human body tissues and cells. However, X-ray and optical transmitted field signals at receiving output of diagnosis CT sensors are disturbed by scattering waves in random bio-medical inhomogeneities
more » ... inhomogeneities around objects of body tissues and cells. Before signal processing by computer, hardware tools of spatial filtering of disturbing scattering fields for absorption characteristics in bio-medical tissues and cells are very useful system functions. Spatial filtering of scattered fields by grid arrays consisting of transversely multiple lossy waveguides is one of excellent device function for spatial filtering in X-ray and optical diagnosis. Spatial filter of grid arrays consisting of multiple lossy waveguides is waveguide array consisting of waveguides with transparent cores and lossy clads. Each waveguide has core size, clad size and waveguide length. Scattered fields in random bio-medical media are incident on input plane of spatial filter array, and coupled to lower modes of low losses for small scattering angles and higher modes of large losses for large scattering angles, in lossy waveguide array. Low angle scattered fields couple to lower modes and large angle scattered fields couple to lossy higher modes. Scattered fields coupled to lossy higher modes are filtered in lossy grid arrays. Mode characteristics in lossy grid arrays excited by scattered field in random bio-medical media are discussed by mode expansion methods using boundary condition at input plane of lossy grid array, and filtered fields at output plane of lossy grid array are shown by integral equations using Green's dyadics. Mode characteristics and filtered fields are also investigated by the Wiener-Hopf method with spectral functions.
doi:10.2529/piers090320052654 fatcat:3tafsj4kvzejfcezfab5skvdci