Broadband short-delay surface acoustic wave delay line

Abstract

The invention discloses a broadband short-delay surface acoustic wave delay line composed of a piezoelectric substrate, sound-absorbing rubber, shielding strips and transducers. The transducers and the shielding strips are arranged on the piezoelectric substrate. Each of the two pairs of transducers is composed of an input transducer and an output transducer, and the two pairs of transducers are correspondingly arranged in parallel to form a dual-channel structure divided into an upper channel and a lower channel. The shielding strips are arranged between the input transducers and the output transducers, and each shielding strip is composed of a plurality of short-circuit metal strips. The center distance between the input transducer and the output transducer in the upper channel is d1, and the center distance between the input transducer and the output transducer in the lower channel is d2. The difference between d1 and d2 is half a wavelength, which enables acoustic signals As1 and As2 generated by the upper and lower channels to be reversed in phase and electric direct signals to be the same in phase. The input transducers and the output transducers are of a sector structure. The strength of electric direct signals is reduced, large bandwidth can be obtained, and the performance is more stable and reliable.

Description

technical field [0001] The invention relates to a delay line, in particular to a wide-band short-delay surface acoustic wave delay line. Background technique [0002] Delay lines are widely used in systems such as radar, communication, navigation, and electronic countermeasures. They have the characteristics of good consistency and high reliability in acoustic wave transmission. [0003] Since the delay time of the delay line is determined by the center distance between the input transducer and the output transducer, the existing traditional short delay line has a very small center distance between the transducers, so the electromagnetic coupling between the input and output is strong , that is, the electrical direct signal is strong, and this signal is undesirable (the signal is a spurious signal, which causes fluctuations in the frequency response passband); in addition, due to the structure of the traditional transducer, it is also difficult to obtain a larger bandwidth, ...

AI Technical Summary

Problems solved by technology

[0003] Since the delay time of the delay line is determined by the center distance between the input transducer and the output transducer, the existing traditional short delay line has a very small center distance between the transducers, so the electromagnetic coupling between the input and output is strong , that is, the electrical direct signal is strong, and this signal is undesirable (the signal is a spurious signal, which causes fluctuations in the frequency response passband); in addition, due to the structure of the traditional transducer, it is also difficult to obtain a larger bandwidth, When in use, it needs to be packaged in a custom metal case to reduce the influence of the electrical through signal, so the cost is high

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