1208 results about "Interdigital transducer" patented technology

A monolithic electronic device includes a substrate, a semi-insulating, piezoelectric Group III-nitride epitaxial layer formed on the substrate, a pair of input and output interdigital transducers forming a surface acoustic wave device on the epitaxial layer and at least one electronic device (such as a HEMT, MESFET, JFET, MOSFET, photodiode, LED or the like) formed on the substrate. Isolation means are disclosed to electrically and acoustically isolate the electronic device from the SAW device and vice versa. In some embodiments, a trench is formed between the SAW device and the electronic device. Ion implantation is also disclosed to form a semi-insulating Group III-nitride epitaxial layer on which the SAW device may be fabricated. Absorbing and/or reflecting elements adjacent the interdigital transducers reduce unwanted reflections that may interfere with the operation of the SAW device.

A disposable pressure sensor includes a substrate and a pressure diaphragm formed upon the substrate. A sensor coil can be provided, comprising a capacitor and an inductor formed on the substrate and surrounded by the pressure diaphragm. The ferrite core is located proximate to the sensor coil, such that when the pressure diaphragm is exposed to a pressure, the diaphragm moves close to the inductor or the capacitor, thereby resulting in a change in the capacitor or the inductor and an indication of pressure. The capacitor can be implanted as an adjustable, trimmable or variable capacitor. The inductor may also be provided as an adjustable or variable inductor and can include the use of a variable capacitor and a PVDF based piezoelectric transducer. When the PVDF layer is under pressure, it can generate an electric field across the interdigital transducer and transmit a signal thereof through an antenna.

A duplexer includes: a transmit filter that is connected between an antenna terminal and a transmit terminal and has a plurality of acoustic wave resonators; a receive filter that is connected between the antenna terminal and a receive terminal and has a plurality of acoustic wave resonators; and a delay line or a longitudinal coupling type resonator that is connected in parallel with at least one of the plurality of acoustic wave resonators of the transmit filter and the plurality of acoustic wave resonators of the receive filter and has at least two IDTs (Interdigital Transducers).

A SAW ladder filter includes grating pads extending from opposing bus bars and interdigital transducer electrodes extending from the grating pads for defining an acoustic aperture. The metalization ratio for the grating pads is greater than that for the interdigital transducer electrodes. Reflector electrodes are disposed on opposing longitudinal sides of the interdigital transducer electrodes. Operation of the filter results in a velocity of the SAW along the grating pads slower than a SAW velocity along the plurality of interdigital transducer electrodes, thus producing a wave guiding effect for optimizing SAW propagation within the acoustic aperture. The grating pads may be longitudinally offset from cooperating interdigital transducer electrodes using minor bus bars.

The invention relates to a magnetic-acoustic surface wave magnetic field sensor and a preparation method thereof, and belongs to the technical field of electronic functional materials and devices. The sensor comprises a piezoelectric thin film, a magnetostrictive thin film and a substrate, wherein the magnetostrictive thin film is positioned between the piezoelectric thin film and the substrate; the thickness of the magnetostrictive thin film is 2-5 times the thickness of the piezoelectric thin film; and an interdigital transducer is arranged on the surface of the piezoelectric thin film, and the interdigital transducer and the piezoelectric thin film constitute an acoustic surface wave device. A layer of SiO2 is covered on the surface of the piezoelectric thin film and the interdigital transducer. When the sensor is in resonant state, if an external magnetic field changes, the Young's modulus of a magnetostrictive layer changes, the propagation speed of acoustic surface waves in a piezoelectric layer can be further affected and then the changes of the external magnetic field can be known by detecting the changes in resonance center frequency. The SiO2 covering layer can compensate for a frequency temperature coefficient of the piezoelectric thin film and realize the frequency temperature coefficient which is close to zero. The sensor has the characteristics of miniaturization, easiness in integration, high sensitivity, good consistency, stability and reliability.

A SAW filter is fabricated at a wafer level for providing desirable temperature characteristics. The filter includes a piezoelectric substrate bonded to a carrier substrate, wherein the coefficient of thermal expansion of the carrier substrate is less than the coefficient of thermal expansion of the piezoelectric substrate. Interdigital transducers are formed on the piezoelectric substrate so as to form a SAW composite die structure. A cap substrate having a coefficient of thermal expansion similar to that of the carrier substrate is bonded to the SAW composite die structure for enclosing the interdigital transducers. Plated vias form signal pad interconnects to input and output pads of the interdigital transducer and a sealing pad formed on the surface of the piezoelectric substrate bonds the SAW composite die structure to the cap substrate.

An acoustic wave sensor apparatus is disclosed, which generally includes a piezoelectric substrate having a surface thereon. One or more interdigital transducers and a passivation layer can be formed upon the piezoelectric substrate. Additionally, an absorbent material can be formed upon the acoustic path (IDTs, electrodes, etc), such that the interdigital transducers respond to a plurality of acoustic waves propagating across the surface of the piezoelectric substrate, thereby providing data indicative of humidity in the vicinity of the piezoelectric substrate, along with the passivation layer and the interdigital transducers. Additionally, one or more heaters can be formed upon a side of the piezoelectric substrate opposite the side of the piezoelectric substrate upon which the interdigital transducers, the passivation and the absorbent material are located. The heater can be preferably configured from a material such as platinum.

A surface acoustic wave device includes at least one interdigital transducer having electrodes of a double-layered structure in which an upper film and an underlying film are laminated. The upper film has a main component of Al and a first metal of Ti added to the main component. The underlying film has a main component of Ti.

A sensor package generally includes a substrate and one or more sensing elements, located on a surface of the substrate. A lid, such as for example a glass cap, is coupled to the substrate such that the lid and substrate define a sealed cavity accommodating the sensing element(s). The lid has at least one conductive via or well electrically coupled to the sensing element(s) inside the cavity and arranged so as to provide an electrical connection to the exterior of the lid for connecting with external circuitry. The substrate can be a piezoelectric substrate and each sensing element can consist of an interdigital transducer such that the substrate and interdigital transducer(s) define a surface acoustic wave sensor. A surface acoustic wave sensor system for sensing torque includes the sensor package and leads wire bonded to the conductive vias for attaching the sensor package to an antenna.

The invention discloses a magnetoelectric surface-acoustic-wave magnetic-field sensor and a manufacturing method thereof and belongs to the technical field of electronic function materials and devices. The magnetoelectric surface-acoustic-wave magnetic-field sensor comprises a magnetostriction substrate, a metal buffer layer and a piezoelectric film, wherein the metal buffer layer is made of metallic titanium or chromium and arranged between the magnetostriction substrate and the piezoelectric film, interdigital transducers with two ports are arranged on the upper surface of the piezoelectric film, and the interdigital transducers and the piezoelectric film constitute a surface-acoustic-wave resonator. Each interdigital transducer comprises an input electrode, an output electrode, an input-end reflecting grating and an output-end reflecting grating, wherein the input-end reflecting grating is arranged on the outer side of the input electrode, and the output-end reflecting grating is arranged on the outer side of the output electrode. The thickness of the piezoelectric film ranges from 0.3-1 micrometer, the thickness of the magnetostriction substrate is larger than two times of wavelength of the surface-acoustic waves. By the aid of the high-orientation piezoelectric film and magnetostriction strips with uniaxial anisotropism and Young's modulus effect, the sensor is miniaturized, high in sensitivity and good in consistency. The manufacturing method is simple and applicable to probing of magnetic fields.

The invention relates to a vibration sensor based on a surface acoustic wave radio frequency identification technology and application for the vibration sensor. The vibration sensor can be used for identifying the identity of a measured object in a radio frequency manner, and can also be used for monitoring whether the vibration acceleration of the measured object exceeds a set threshold value or not and then recording the vibration acceleration of the measured object; a surface acoustic wave device comprises an antenna, a piezoelectric substrate, an interdigital transducer, reflecting gratings and an elastic element; radixes in the reflecting gratings are used for coding radio frequency tags; the 1-3 reflecting gratings are connected with the elastic element, and then a normally open loop is formed; when the vibration acceleration induced by the vibration sensor exceeds the set threshold value, the reflecting gratings, the elastic element and matched networks jointly form a closed loop; and features of echo signals reflected back to a reader are changed, so that the vibration sensor can alarm after the vibration acceleration in a superthreshold is recorded. Compared with the prior art, the vibration sensor has the characteristics that a measuring method is simple, multidimensional and multi-range measurement can be realized, the vibration sensor is wide in application, and the like.