2次元周期構造をもった弾性表面波電極の特性
Characteristics of the SAW Two-Dimensionally Periodic Transducer (2-PT)

Showko Shiokawa, Toyosaka Moriizumi, Tsutomu Yasuda
1977 Acoustical Science and Technology  
An ordinary surface acoustic wave ( SAW ) inter・ digital transducer has a uniform launching aperture in the x direction ( parallel to the wavefronts ) , and periodic finger pairs in the z direction ( normal to the wavefronts ) , Hence ,三 t has one −dimensional perio . dic... ty only in the x direction . In this pape τ we present anew type of a SAW transducer with two . dimen . sionally periodic electredes , whose co 面 guration has periodic 菫 ty not Qnly in the x d玉 rect 圭 on but also in the x
more » ... but also in the x direction , ( Fig . 1 ( b ) ) , It is possible to predict the beam . pro 丘les emitted from the two . dimensionally periodic transducer ( 2 − PT ) using the 皿 ethod of the angular spect 川 m of plane wave § ( ASPW ) . It has been shown from this analysis that the 2 − PT causes de且ection of the SAW beam , and that the deflecting angle 三 s determined by θ * = tan − 12t / 2x , where Az and λ x are the per ... odic le ロ gths ... nthe z and x directions , respect 玉 vely . There are tw 。 advantages for this 2 − PT ; ( 1 ) the SAW beam can be scann ' ed by the de 且ection when the exciting frequency is swept , and ( 2 ) it is possible tQ decrease the sidelobe levels in a SAW 丘1ter substantially by controlling the angles of the SAW wavefronts . In order to verify the theo 爬 tical results , samples of 2. PT have been designed and fabricated on a Y − cut LiNbO3 wafer and a sputtered ZnO film on glass . Experimental configurations of these are shown in Figs.7and 8 , respectively . The observed propagation patterns by the FTH5 , techniqueare shown in Figs.9 and 10. Figs. 11 and 12 illustrate the experimental and theoretical fre凾 quency characteristics for the 2 − PT ' s on a LiNbOs wafer and a ZnO 丘lm , respectively . Comparing the experimental results with the theoretical predictions , resonable agreements have been obtained . In conclusion , it is found that the 2 − Pt has pro _ mising characteristics for acousto . optic deflectors and SAW bandpass 丘lters ,
doi:10.20697/jasj.33.10_571 fatcat:xxg2s6mdx5aqrplnyk4r5qxjxq