A low power apparatus for measuring various process parameters and/or physical properties of a fluid or gas medium by measuring the change of a wave signal or time dependent signal as it traverses the fluid or gas medium, the apparatus comprising: at least one transmission transducer for providing a transmitted wave or time dependent signal for injection into the fluid or gas medium; at least one reception transducer, displaced from the transmission transducer for receiving a received wave or time dependent signal from the fluid or gas medium; and an analog signal processor, coupled to the reception transducer, for processing of the received wave or time dependent signal such that a short interval of the processed received wave or time dependent signal is extracted.

Low power signal processing and measurement apparatus

In order to reduce scattering losses during the transmission of a surface acoustic wave signal, a surface acoustic wave arrangement has a junction between two mutually offset surface acoustic wave structures designed so that the finger period is reduced in the region of the junction, and varies continuously in the region of the junction.

Surface acoustic wave arrangement with a junction region between surface acoustic wave structures having a decreasing then increasing finger period

A surface acoustic wave resonator includes a piezoelectric substrate and an interdigital transducer (IDT) that includes electrode fingers exciting a surface acoustic wave on the piezoelectric substrate, a first region at a center of the IDT, and a second region and a third region at opposite sides of the IDT In the IDT, a line occupation rate at which an electromechanical coupling coefficient becomes a maximum is different from the line occupation rate at which reflection of the surface acoustic wave becomes a maximum

Surface acoustic wave resonator, surface acoustic wave oscillator, and surface acoustic wave module device

A surface-acoustic-wave device comprises a piezoelectric substrate and first and second comb-shaped electrodes each having a bus-bar portion parallel to a propagation direction of a surface acoustic wave in the substrate. Respective electrode fingers are periodically formed on the piezoelectric substrate and extend in directions perpendicular to the propagation direction, wherein the electrode fingers of the first comb-shaped electrode and the electrode fingers of the second comb-shaped electrode are separated away from the bus-bar portion of the opposing comb-shaped electrode. The respective electrode fingers being periodically arrayed in the propagation direction of the surface-acoustic-wave, and the electrode fingers of each comb-shaped electrode are inclined at root portions thereof outwardly right and left from the bus-bar portion of the corresponding comb-shaped electrode so that the inclined portions of the electrode fingers face a direction of a leaking surface-acoustic-wave perpendicularly.

Surface Acoustic Wave Device

A novel programmable SAW filter with switchable multi-element interdigital transducers (IDTs) controlled by a microprocessor or a computer is provided that realizes the tunability of both center frequency and bandwidth of the SAW filter. The filter possesses the feature of the programmability of both center frequency and 3 dB bandwidth. As an example design, the center frequency of the SAW filter ranges from 126.8 MHz to 199.1 MHz while the 3 dB bandwidth ranges from 18.8 MHz to 58.9 MHz. The multi-input configuration increases the programmability of the device and improves insertion loss. A matching network for the programmable SAW filter further improves insertion loss level and stopband attenuation. A resistance weighting method has been applied to improve in band ripple with the passband ripple being reduced from 6.44 dB to 1.37 dB after resistance weighting. The prototype of programmable SAW filter simplifies the device structure and fabrication process by eliminating the tap weighting and summing circuits, resulting in a smaller device and lower costs. Moreover, frequency response shaping is realized without apodization.

Programmable surface acoustic wave (SAW) filter

A surface acoustic wave element has a low insertion loss in one direction and a wide band width. This surface acoustic wave element has first and second interdigital electrodes each having a thickness on a piezoelectric or electrostrictive substrate. In a first interdigital electrode for exciting a surface acoustic wave, positive and negative electrodes are alternately arranged such that their electrode widths and periods are gradually decreased in a direction of propagation of the surface acoustic wave. In a second interdigital electrode for receiving the surface acoustic wave, positive and negative electrodes are alternately arranged such that their electrode widths and periods are gradually increased or decreased in the direction of propagation of the surface acoustic wave.

Surface acoustic wave element having a wide bandwidth and a low insertion loss

A surface acoustic wave convolver includes first and second interdigital electrodes for exciting surface acoustic waves and an output electrode for detecting the surface acoustic waves to extract a convolution output as an electrical signal, the first and second interdigital electrodes and the output electrode being formed on a piezoelectric or electrostrictive substrate. In order to improve convolution efficiency and obtain wide-range characteristics, each of the first and second interdigital electrodes has a predetermined thickness, the first interdigital electrode is arranged such that positive and negative electrodes are alternately arranged so as to have electrode widths and periods which are gradually decreased toward the output electrode, the second interdigital electrode is arranged such that positive and negative electrodes are alternately arranged so as to have electrode widths and periods which are gradually increased toward the output electrode, and the second interdigital electrode has a double electrode structure in addition, in order to reduce ripples in frequency characteristics, the output electrode are divided into a plurality of pieces, and two end portion of each of the first and second interdigital electrodes are weighted.

Surface acoustic wave convolver

PURPOSE:To provide an acoustic surface wave convolver which has high convolution efficiency and a wide band characteristic. CONSTITUTION:In the acoustic surface wave convolver equipped with first and second interdigital electrodes 4-7 for exciting acoustic surface waves and an output electrode 8 for detecting these acoustic surface waves and extracting a convolution output as an electric signal on a piezoelectric or electrostrict substrate, the first and second interdigital electrodes 4-7 have prescribed thickness, the first interdigital electrodes 4 and 5 are constituted by alternately arranging positive and negative electrodes having the electrode width and the cycle gradually shortened toward the output electrode 8, the second interdigital electrodes 6 and 7 are constituted by alternately arranging positive and negative electrodes having the electrode width and the cycle gradually prolonged toward the output electrode 8, and the second interdigital electrodes 6 and 7 have double electrode structure.

Acoustic surface wave convolver

PURPOSE:To provide a surface acoustic wave element having the characteristic of a low insertion loss for one direction, and a wide band characteristic. CONSTITUTION:The surface acoustic wave element in which an interdigital electrode having a thickness is provided on a piezoelectric or electrostrictive substrate 1, is equipped with a first interdigital electrode which excites a surface acoustic wave in which positive and negative electrodes 4 and 5 whose electrode width and period are gradually shortened in the transmitting direction of the surface acoustic wave are alternatively arranged, and a second interdigital electrode which receives the surface acoustic wave in which positive and negative electrodes 6 and 7 whose electrode width and cycle are gradually lengthened in the transmitting direction of the surface acoustic wave are alternately arranged. Also, this element is equipped with a third interdigital electrode which excites the surface acoustic wave in which the positive and negative electrodes whose electrode width and cycle are gradually shortened in the transmitting direction of the surface acoustic wave are alternately arranged, and a fourth interdigital electrode which receives the surface acoustic wave in which the positive and negative electrodes whose electrode width and period are gradually shortened in the transmitting direction of the surface acoustic wave are alternately arranged.

Kazuhiko Yamanouchi

Papers

Surface acoustic wave element having a wide bandwidth and a low insertion loss

Surface acoustic wave convolver

Acoustic surface wave convolver

Surface acoustic wave element and filter