Surface Acoustic Wave Delay Line Research Articles

Surface acoustic wave delay lines with small temperature coefficient

Surface acoustic wave delay lines having a vanishing first-order temperature coefficient of delay time near room temperature have been constructed. The devices were operated near 60 MHz and had about 5 µs delay. The surface waves, generated and received using interdigital electrodes, were propagated along the twofold crystallographic axis of ST-cut quartz. The phase delay change as a function of temperature has a parabolic temperature dependence with a second-order coefficient of approximately 31.5 × 10-9/° C2.

Analog Matched Filter Using Tapped Accoustic Surface Wave Delay Line (Correspondence)

VHF experiments are described employing 11- and 50-tap surface acoustic wave delay lines fabricated on crystalline quartz as analog matched filters. Excellent correlation characteristics were observed for a 63-bit maximal length biphase code.

1.75-GHz ACOUSTIC-SURFACE-WAVE TRANSDUCER FABRICATED BY AN ELECTRON BEAM

Surface-acoustic-wave interdigital transducers operating at 1.75 GHz have been fabricated on y-cut z-oriented LiNbO3 and y-cut x-oriented quartz substrates by electron-beam techniques. The transducers consist of 25 pairs of interleaved aluminum ``fingers'' 0.3 μ wide and 0.7 μ apart. Used as a surface acoustic wave delay line, the insertion loss has been measured to be as low as 25 dB with a bandwidth of 70 MHz for 2.2-μsec delay. The parameters of the equivalent circuit of the transducer have been measured and agree with the theoretical calculation.