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Results are summarized of a finite element comparison of phased array transducers involving a multi-layer composite hybrid versus a single crystal.

Phased array transducers using PZT-5H and two multi-layer composite hybrids are examined and compared. Simulated and experimental results are summarized.

The presence of a space chargein a ferroelectric thin film, in the presence of Schottkey barriers at two electrode/film interfaces, are investigated. Numerical simulation, using Landau-Khalatnikov, theory, is employed.

An innovative concept for design of an impedance-matching structure for air-coupled ultrasonic transducers is presented and discussed.

Compact dual-log spiral (DLS) resonators with an unusual geometry are examined and tested in microstrip configuration.

Design of a low-cost pulse generator for ultrasound imaging is discussed. Pulses from 10 to 500 ns have been generated.

Polyvinylidene fluoride (PVDF), a piezoelectric material, has various applications, and models of devices would be useful to engineers. But the benefit of such models depends on the accuracy of models' material properties. The aim, here, is to measure elastic, dielectric and piezoelectric properties over a frequency range, including the imaginary part (loss) of these properties.

Acoustic properties of gadolinium gallium garnet (GGG), Si, Ge single crystals and SiO[subscript 2] glasses as standard specimens for calibrating the line-focus-beam ultrasonic material characterization (LFB-UMC) system. Elastic constants and densities were determined at around 23 degrees centigrade.

Directivity and other properties of natural single-phase unidirectional transducers (NSPUDT) propagation directions on ST-cut quartz are investigated.

Reflection coefficient calculations for a metallic film discontinuity on langasite, langanite, and gallium phosphate are provided. The perturbation theory is used as a method of calculating the reflection coefficient in space.

Source amplitude fluctuations, or AM noise, in residual phase noise measurements are examined. Two methods to reduce it are described.

Use of the leaky mode propagation method to model 1-D finite-height, finite-length fully etched waveguiding bandgap structures is proposed. Advantages of the model include an absence of any a priori assumptions and approximations, the rapidity and stability of the convergence, and the amount of information it enables someone to quickly determine.

Performance of a micro-electro-mechanical-systems (MEMS) transducer are investigated. A scanning heterodyne interferometry system is used.

Phase noise in surface area wave (SAW) resonators, related to surface particle motion, is investigated experimentally and theoretically. It is suggested that research on particle motion above the device substrate could lead to a better understanding of the phase noise mechanism and facilitate construction of oscillators with improved performance.

Measurements of the static phase noise and vibration sensitivity of thin film resonator (TFR) , operating at 640 MHz and 2110 MHz, are examined. It is shown that the short-term frequency instability of the filters is small, compared with that induced in the oscillator signal by phase modulation (PM) noise.

A method is described for forming both transient and permanent, 1- and 2-D gratings in nematic liquid crystals.The method can easily be controlled by externally applied ac fields.

The efficiency of piezoceramic transducers (PCT), excited at resonance and antiresonance frequencies, is investigated. It is shown that the interrelation of resonance and antiresonance quality factors depends mainly on the imaginary part of the piezocoefficient, which is most essentially influential at the fundamental antiresonance frequency.

An increasing number of surface acoustic wave (SAW) devices behave as waveguides in that they accommodate all kinds of waveguide modes. Here, the traditional scalar potential concept is combined with the stack matrix approach to construct a complete set of modes existing in SAW waveguiding structures.

It is shown that a system that relies on linear transmitting and receiving arrays of general shape can generate well-behaved point-spread functions (PSF) if transmitted and received signals are appropriately weighted. Examples that illustrate the theory are two perpendicular line arrays and two circular arrays of different radii.

A ferroelectric-based structure for an integrated microphone and microspeaker is described. The device is suitable for applications that require high-quality micro-acoustic devices.

A time domain-based approach is described, for computing the response of a piezoelectric transducer, taking possible time-varying elements into account. The approach can be applied to any element exhibiting behavior that varies in time, whether it be electrical or acoustical.

Design and performance of high frequency, single-element transducers that incorporate diverse materials are investigated. Materials investigated include 1-3 lead zirconate titanate (PZT) fiber composite, lead titanate (PbTiO[subscript 3] ceramic, poly(vinylidene fluoride) (PVDF) film, and lithium niobate (LiNbO[subscript 3] single crystal.

An accurate, distributed model for capacitive micromachined ultrasonic transducers (cMUT) is described. Unlike previous work, the mechanical load of the cavity behind the diaphragm is not omitted.

A multi-degree-of-freedom (MDOF) ultrasonic motor is described. It has few parts and relies on inexpensive thick-film technology.