Field transformation in irregular waveguide structures and analysis of left-handed material.

摘要

Compact elements in integrated circuits are critical for high capacity communication and signal processing. Irregular waveguide structures with a size of several wavelengths long have been synthesized to perform various operations, many of which were not previously possible by adiabatic or periodic concepts. These devices have a large number of degrees of freedom for optimization and strong scatter, resulting in significant evanescent fields. An irregular waveguide structure in the microwave regime has demonstrated wavelength-dependent transformation with virtually no loss. Experimental results for a device operating at a communication infrared suggest applications in optical components. Mode selective reflectors and phase shifters have also been designed.; Left-handed or negative refractive index material can amplify the evanescent fields in a surrounding right-handed medium. This characteristic makes sub-wavelength resolution possible, which is important in superlens imaging and high-precision lithography. The impact of minute loss on the field behavior has been investigated theoretically by a perturbational treatment. Power dissipation in the slab suggests that the growth of the evanescent field is adversely impacted. It is also found numerically that there is circulating power accompanied with the use of such material.