| 摘要 |
<p>A novel design for producing bandpass filters with essentially squera shapes with little or no ripple in the passband zone is provided. A multi-layer multi-cavity filter comprises an array of at least n cavities. Each of the n cavities has two quarter wave reflecting stacks, each comprising layers of material of alternative high and low refractive index. The two quarter wave reflecting stacks are separated by a half wave or multiple half wave spacer layer of dielectric material. The array of at least n cavities has at least one or more inner cavities and one or more outer cavities adjacent a substrate and one or more outer cavities adjacent an outward medium. Each of the n cavities is separated by a quarter wave layer of low refractive index material. At least an additional half-wave layer is provided in addition to the quarter wave layers of one or more stacks of one or more of the inner cavities to yield at lean a three-quarter wave layer within said one or more of the stacks for lessening ripple. <IMAGE></p> |
