Showing papers on "Interdigital transducer published in 1968"

Frequency response of an interdigital transducer for excitation of surface elastic waves

Abstract: Excitation of elastic waves in a piezoelectric solid by an interdigital transducer, in terms of a simplified model, has been analyzed using Lamb's integral solution. The transducer generates three types of disturbances propagating at the velocities of irrotational, equivoluminal, and Rayleigh waves. While the amplitudes of the former two waves diminish as the three-half power of the distance from the transducer, that of the latter does not decay with distance on the surface. Dependence of particle displacement of the waves on electric fields, number of electrodes, electrode width, and wave numbers has been derived. It has been shown that a conventional interdigital transducer, in which all the electrode widths and all the spacings are respectively equal among themselves, can respond to fundamental and odd harmonic excitations, but not to the even harmonics. Means to improve the insertion loss and the bandwidth of the transducer are discussed. A flat overall frequency response can be synthesized by parallel operation of two or more transducers, the fundamental frequencies of which are properly staggered.

High‐performance lithium niobate acoustic surface wave transducers and delay lines

Abstract: Radiation resistance measurements have been made on 20 electrode pair interdigital transducers deposited on poled crystals of lithium niobate, for a variety of cuts and propagation directions, with the objective of determining optimum geometries for the efficient wideband generation of acoustic Rayleigh waves. Using Y cut, Z axis propagating lithium niobate and five‐electrode pair transducers a 100‐MHz delay line has been constructed with an insertion loss of 11.5 dB at a delay of 8.9 μsec, and a −3‐dB bandwidth of 24 MHz.

Temperature stabilized piezoelectric crystal transducer and oscillator

Abstract: A CRYSTAL TRANSDUCER AND AN OSCILLATOR CIRCUIT IS DISCLOSED IN WHICH A TEMPERATURE GRADIENT IS APPLIED BETWEEN THE CRYSTAL FACES. ONE FACE IS HELD AT A PREDETERMINED REFERENCE TEMPERATURE WHILE THE TEMPERATURE OF THE OTHER FACE VARIES WITH THE ENVIRONMENT TO WHICH IT IS EXPOSED. FOR THIS ARRANGEMENT A LINEAR RELATIONSHIP EXISTS BETWEEN THE TEMPERATURE GRADIENT AND THE NATURAL RESONANCE OF THE CRYSTAL. APPLICATIONS AS TEMPERATURE SNSOR, MICROBALANCES AND PARTICULAR MODES OF OPERATING THE TRANSDUCER ARE DISCLOSED.