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Interdigital transducer
About: Interdigital transducer is a research topic. Over the lifetime, 2706 publications have been published within this topic receiving 27976 citations.
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TL;DR: A comparison of the usability of different wave types is presented in this article, where planar technologies are used for fabrication of the acoustic-wave devices, which will be given of gas sensors, biochemical sensors in liquids, viscosity and density sensing and highvoltage sensing.
254 citations
TL;DR: In this paper, the electric field distribution from a surface wave interdigital transducer is investigated for anisotropic, small-coupling propagation medium, and the capacitance of the transducers is derived.
Abstract: The electric field distribution from a surface wave interdigital transducer is investigated. Expressions for the various spatial harmonics and the capacitance of a transducer applied on an anisotropic, small-coupling propagation medium are derived. Experiments are consistent with the calculations.
245 citations
Patent•
09 Mar 1995
TL;DR: In this article, a plurality of discrete transducers are formed on an initially flat flexible substrate together with electrically conductive tracks, through which the transducers will be energized in use.
Abstract: In a method of manufacturing an ultrasonic transducer array a plurality of discrete transducer elements are formed on an initially flat flexible substrate together with electrically conductive tracks, through which the transducer elements will be energised in use, the flexible substrate with the discrete transducer elements and conductive tracks mounted thereon then being formed into a cylinder and mounted on the end of a catheter tube, the substrate being radially outwardly of the transducer elements so that it is in a position to act also as an acoustic matching layer between the material of the transducer elements and the human tissues or blood when in use.
243 citations
TL;DR: The breadth of applications and measurement sensitivity of SAW biosensor systems should be greatly enhanced and bioparticles can also be concentrated by this method, and it is verified that yeast cells are not lysed by the SAW radiation during concentration.
Abstract: A rapid particle concentration method in a sessile droplet has been developed using asymmetric surface acoustic wave (SAW) propagation on a substrate upon which the droplet is placed. Due to the asymmetry in the SAW propagation, azimuthal bulk liquid recirculation (acoustic streaming) is generated. Once the local particle concentration is sufficiently high within a particular streamline of the acoustic streaming convective flow, shear-induced migration gives rise to an inward radial force that concentrates the particles at the centre of the droplet. In this paper, a SAW device consists of a 0.75-mm thick, 127.68° Y–X-axis-rotated cut, X-propagating LiNbO3 for a substrate and an interdigital transducer electrode (IDT) with 25 straight finger pairs in a simple repeating pattern, 12 mm aperture, and a wavelength of λ = 440 μm was patterned on the substrate. The IDT was then driven with a sinusoidal signal at the resonance frequency f
0 of 8.611 MHz. To investigate the effect of particle type and size on the concentration process, three types of particles were used in this study, including fluorescent particles (1 μm), polystyrene microspheres (3, 6, 20, 45 μm), and living yeast cells (10–20 μm). Different RF powers were applied ranging from 120 to 510 mW. The concentration processes occurs within 2 to 20 s, depending on the particle size, type and input radio frequency (RF) power, much faster than currently available particle concentration mechanisms due to the large convective velocities achieved using the SAW device. Moreover, this concentration method is efficient, concentrating the particles into an aggregate one-tenth the size of the original droplet. Most importantly, bioparticles can also be concentrated by this method; we have verified that yeast cells are not lysed by the SAW radiation during concentration. By using the rapid concentration process described in this work, the breadth of applications and measurement sensitivity of SAW biosensor systems should be greatly enhanced.
228 citations
TL;DR: In this paper, the authors used an interdigital electrode structure overlaid with a piezoelectric film for the excitation of surface acoustic waves on a non-piezolectric material.
Abstract: This paper is concerned with the theory of excitation of surface acoustic waves on a nonpiezoelectric material, by using an interdigital electrode structure overlaid with a piezoelectric film The impedance and capacity of such transducers have been worked out The results are given in terms of Δv/v, the perturbation in acoustic wave velocity when a perfect conductor is placed in the position of the transducer A computer program which calculates surface wave propagation on a layered medium consisting of a film on a substrate, with arbitrary elastic and piezoelectric properties for both media, has been used to determine Δv/v, and hence the coupling coefficients and radiation resistance of the interdigital transducer As a function of piezoelectric film thickness, two peaks in coupling are observed The results for the interdigital couplers are in quantitative agreement with experiments employing single‐crystal materials Data for experiments using sputtered piezoelectric films also give qualitative agreement with the theory If high‐quality crystalline layers are used, the theory suggests that interdigital couplers on nonpiezoelectric delay lines with properties comparable to or better than the present piezoelectric delay lines may be achievable
223 citations