John A. Kosinski

Piezoelectric materials for acoustic wave applications

Piezoelectric materials for acoustic wave applications have changed markedly over the past 20 years in terms of both the types of materials available and the quality of individual samples. The total family of acoustic wave materials now includes piezoelectric glass-ceramics having crystallographic and polar orientation and crystals having symmetry classes mm2, 32, 3m, 4mm, 6mm, and 4/spl macr/3m. The symmetry classes 6mm and 4/spl macr/3m also occur frequently in piezoelectric semiconductor materials that are now available in both bulk and thin-film configurations. In this paper, we bring together and extract the various reported values of the material constants mainly of interest for surface acoustic wave (SAW) device applications. We identify for the user community those sets of constants from which SAW design calculations can reliably be made, and discuss the constants and their reliability for langasite, lithium niobate/lithium tantalate, and dilithium tetraborate. The relevant material constants include: mass density /spl rho/, elastic stiffness c/sub ij/, piezoelectric stress e/sub ij/, dielectric permittivity /spl epsiv//sub ii/, and the thermal expansion coefficients /spl alpha//sub ii/. Except for the semiconductor materials, only data published after 1978 are included, since the reference literature (Landolt-Bornstein) amply covers those years prior to 1978.<<ETX>>

Designing for low acceleration sensitivity

Recent advances in acceleration sensitivity measurement and modeling are discussed, with an emphasis on what these advances indicate in terms of designing for low acceleration sensitivity. The design suggestions are separated into two parts, namely, those that use the crystal resonator as a mechanical vibrator and those that use the crystal oscillator as an electronic circuit. Such topics as symmetry considerations, metallization, mounting etc., in both bulk acoustic wave (BAW) and surface acoustic wave (SAW) devices are discussed for the former, while for the latter the equivalent circuit modeling of crystal resonators and other loop components is addressed.<<ETX>>

Mass loading measurements of quartz crystal plates

Various methods of determining electrode mass loading are presented, and measurements of mass loading using several of these techniques are compared. Variations between the values of mass loading obtained by the different techniques are discussed and a model is proposed to explain the differences. A simple first approximation to the effects of lateral boundedness which provides qualitative insights as to the cause of the variations is presented.<<ETX>>

Effects of piezoelectric coupling on energy mapping of thickness-shear modes

Energy trapping of thickness-shear vibration modes in a partially electroded piezoelectric crystal plate of monoclinic symmetry is analyzed. Effects of piezoelectric coupling on energy trapping are examined. Results show that the effect of piezoelectric coupling is comparable to the effect of electrode mass and needs to be included in the analysis of energy trapping.

Two-dimensional equations for electroelastic plates with relatively large shear deformations

A set of two-dimensional, nonlinear equations for electroelastic plates in moderately large thickness-shear deformations is obtained from the variational formulation of the three-dimensional equations of nonlinear electroelasticity by expanding the mechanical displacement vector and the electric potential into power series in the plate thickness coordinate. As an example, the equations are used to study nonlinear thickness-shear vibrations of a quartz plate driven by an electrical voltage. Nonlinear electrical current amplitude-frequency behavior near resonance is obtained. The equations and results are useful in the study and design of piezoelectric crystal resonators and the measurement of nonlinear material constants of electroelastic materials.

Range-Doppler Resolution of the Linear-FM Noise Radar Waveform

This research considers the linear-FM (LFM) of a noise radar waveform for resolving targets when channel noise and four popular radar sidelobe weighting functions are considered. By using large time-bandwidth products and systematically varying the phase scaling factor κ, results from the digital matched filter output provide evidence that the LFM noise waveform 1) has range-Doppler resolution similar to conventional chirp waveforms and 2) has a low probability of intercept (LPI) similar to random noise waveforms. We acquire the results using a computer-based simulation and verify the location of target peaks using the chirp waveform output for both stationary and moving target cases.

Low Probability of Interception of an Advanced Noise Radar Waveform with Linear-FM

This research considers an advanced pulse compression noise (APCN) radar waveform possessing salient features from linear-FM (LFM) and noise waveforms. A cross-correlation model considering several chirp waveform profiles is used to simulate the output of a passive electronic intelligence (ELINT) intercept-receiver. By doing so we are able to demonstrate the low probability of interception (LPI) characteristic of the APCN waveform for different κ values.

Inclusion of non-uniform distribution of motion effects in the transmission-line analogs of the piezoelectric plate resonator: theory and experiment

The inclusion of the effects of a non-uniform distribution of vibratory motion in Ballatos exact transmission-line analogs of the piezoelectric plate resonator is addressed on both theoretical and experimental bases. It is shown that both the mass loading (series inductance) and piezoelectric coupling (transformer) terms are modified by the non-uniform distribution of motion. Typical magnitudes of the required correction factors are discussed, and representative experimental data are presented.<<ETX>>

Fiber Bragg grating sensors for seismic wave detection

The work presented in this paper demonstrates a sensing technology for unattended seismic sensors based on the optical fiber Bragg grating. This kind of sensor can perform accurate measurements of the seismic activity due to their high sensitivity to dynamic strains caused by small ground vibrations. One of the applications is its deployment in the battlefield remote monitoring system to track and geo-locate the presence of personnel, wheeled vehicles, and tracked vehicles. The experimental data of the field test are shown as well as the comparable result with commercial seismic sensors.

Theoretical and experimental evidence for superior intrinsic Q of STW devices on rotated Y-cut quartz

Several advantages of STW devices are by now well known. These include simultaneous moderately high acoustic velocity and zero temperature coefficient of frequency, along with extremely high power handling capability. In this paper we present theoretical and experimental evidence of an additional advantage of STW devices on quasi-AT-cut quartz: the intrinsic Q of such devices is superior to that of ST-cut SAW devices and AT-cut BAW devices, with the STW having Q/spl times/f/spl ap/3.25/spl times/10/sup 13/ Hz.