| 摘要 |
A novel design for producing bandpass filters with essentially square shapes with little or no ripple in the passband zone. Filters are of the all-dielectric type consist of multiple cavities (10a,10b,10c) of bandpasses. Quarter wave thick layers (12) of low index material separate all of the cavities from each other. Multiple half-waves may be added to the outer cavity quarter-wave stacks in particular. This invention provides the addition of half wave to some of the inner cavity stacks to remove ripple that would otherwise be present. Together, these additional half wave layers added to the outer and inner cavities sharpen the transition from low transmission to high transmission without unduly adding ripple to the high transmission zone. <IMAGE> |
