| 摘要 |
A reflective grating (36) for a SAW filter (10) or resonator. The reflective grating (36) is formed by selectively dithering grating grid lines (38) with respect to a uniform spaced grid of M number of grid lines (38) per each N wavelength (lambda) of the grating (36) (Nlambda/M), where lambda is the wavelength of the center of the frequency band of interest, M and N are integers and M>N. M and N are selected so that the grating (36) does not have a net reflection when all of the grid lines (38) are uniformly spaced. By controlling the dithering pattern of the grid line in each sampling period of Nlambda, any desired net distributed reflectivity from the grating can be implemented in both magnitude and phase.
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