| 摘要 |
PURPOSE:To maximize the directivity by arranging the phase shifter so as to mutually cancel the frequency variation at opposite propagation and using a lumped constant phase shifter to make the frequency characteristic of phase difference variable. CONSTITUTION:LiNbO3 of 128 deg. rotation Yaxis cut X axis propagation is used as a piezoelectric substrate 17, unidirectional electrodes with constant opening length of 20 pairs are used for input electrodes 18 and unidirectional electrodes of 60 pairs whose cross width is changed and weighted are used for output electrodes 19. The phase shifter is constituted that an inductance Lm:7 and a capacitance Cm:8 are connected in parallel in series with a resistor R:6. The phase shifter is connected in series with the reflection electrode 2 and the series circuits are connected in parallel with the electrode 1.
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