Design of bandpass filters composed of dielectric layers separated by gratings of strip conductors.

We derive the design formulas for novel multilayer bandpass filters in which every dielectric layer (resonator) is separated from the adjacent layer or external medium by a grating of strip conductors. Every grating acts as a semi-reflecting mirror. Such novel filters have wide stop bands compared to conventional filters with multilayer dielectric mirrors between resonators at the same passband width.

Multilayer bandpass filter with extended lower and upper stop bands.

We propose a novel design for a multilayer bandpass filter in which every resonant dielectric layer is separated from adjacent dielectric layers or from the ambient by a nonresonant grating of strip conductors on the layer interface. Here, every grating acts as a mirror with specified transparency. Relative to the conventional multilayer bandpass filter with multilayer dielectric mirrors, the proposed filter has multiply extended stop bands below and above the passband.

Design of optical bandpass filters based on a two-material multilayer structure.

An easy method for designing filters with equalized passband ripples of a given magnitude is proposed. The filter, which is made of two dielectric materials, comprises coupled half-wavelength resonators and multilayer mirrors. The filter design begins with the synthesis of the multimaterial filter prototype whose mirrors consist of quarter-wavelength layers.