38results about How to "Lower Frequency Temperature Coefficient" patented technology

The invention discloses a FBAR (film bulk acoustic resonator) substrate and a preparation method thereof. The FBAR substrate is of a W/piezoelectric film/W/ DLC/air gap/Si structure. The FBAR substrate with a W/piezoelectric film/W/ DLC/air gap/Si structure has the characteristics of high frequency, high Q (quality) and good frequency stability. The FBAR substrate can be used for manufacturing filters and duplexers and the like in wireless communication systems, and also can be used for manufacturing high-performance sensors in combination with sensitive films.

A B-substituted BNT microwave dielectric ceramic material and its preparation method belong to the technical field of a functional material. The general chemical formula of the microwave dielectric ceramic material is Ba3.75Nd9.5Ti18-y(M,N)yO54, wherein y is less than or equal to 2.5 and greater than or equal to 0.6; the microwave dielectric ceramic material is prepared by steps of: burdening BaO, Nd2O3, TiO2, oxides of metallic elements M and N according to mole ratio of the general chemical formula, carrying out ball-milling, presintering and sintering; an oxide of the element M is Nb2O5; and an oxide of the element N is one or more compounds selected from Al2O3, MgO, ZnO, Co2O3 and NiO. According to the invention, simultaneous substitution of high and low valence elements is carried out in the B position of Ba6-3xNd8+2xTi18O54. The microwave dielectric ceramic material prepared by a one-step synthesis process has high dielectric constant, low loss characteristic and low frequency-temperature coefficient, can meet requirements in the microwave communication industry, and is especially suitable for manufacturing of RFID tags.

The present invention relates to the dielectric material with low dielectric constant and low loss for microwave functional module and its preparation process. The preparation process includes mixing material including MgO, Al2O3, SiO2, ZnO and B2O3 and founding glass; quenching glass to obtain transparent vitreous body without recrystallization; wet ball grinding, adding TiO2 as temperature coefficient regulating agent, mixing, ball milling, drying, pressing into disc and sintering to obtain the material of the present invention. The MgO-Al2O3-SiO2-ZnO-B2O3 system with TiO2 temperature coefficient regulating agent has low dielectric constant, low loss, low temperature coefficient of frequency, low thermal expansion coefficient and other advantages, and may be used in producing various microwave modules.

A TE01 mode dielectric filter comprises a cavity, a cover plate, dielectric resonators, T-shaped coupling rods, tuning screws, SMA electric connectors and fastening screws. The TE01 mode dielectric filter is characterized in that cross couplings of the filter are all positive, and a main coupling is provided with two negative couplings positioned between the dielectric resonators R1 and R2 and between the dielectric resonators R6 and R7 respectively by the aid of the novel T-shaped coupling rods. Due to the fact that all cross couplings of the filter are positive and implemented through coupling holes, compared with a traditional dielectric filter with negative cross couplings implemented through probes, the TE01 mode dielectric filter has the advantages that introduced parasitic couplings are small, introducing redundant cross couplings for overcoming influences of the parasitic couplings is not needed, and reliability of the filter is improved. In addition, the novel T-shaped coupling rods are low in chromatic dispersion and simple in processing, fine tuning of coupling can be realized by the aid of the tuning screws, repeatedly demounting the cover for altering the sizes of the coupling rods during debugging of the filter is avoided, and accordingly debugging workload is reduced.

The invention discloses a method for machining an MEMS resonant structure. The method includes: providing silicon wafer as substrate silicon, and growing a first mask layer on the surface of the substrate silicon; machining open patterns on the first mask layer; removing parts of the first mask layer and the substrate silicon which are corresponding to the open patterns by dry etching, and forming groove structures on the substrate silicon; growing second mask layers, forming the second mask layers on groove side walls of the groove structures and the groove bottoms, and forming a composite mask layer on the surface of the substrate silicon; removing the second mask layers by dry etching, and completely removing the second mask layers of the groove bottoms; etching the substrate silicon again by dry etching, enabling the groove structures to be deepened, and enabling newly etched groove side walls not to be covered by mask layers; by wet etching, enabling the inside of the substrate silicon to be communicated with the open pattern to form a cavity; depositing lower electrodes, piezoelectric function materials and upper electrodes; and patterning and releasing the resonant structure by dry etching.

The invention belongs to the technical field of microwave dielectric ceramic materials, and particularly relates to a barium niobate system microwave dielectric ceramic material. BaCO3, Nb2O5, ZnO, CoO and NiO are used as raw materials to synthesize a main sintering block, SiO2, BaO, CaO, B2O3 and Li2O are used as raw materials to synthesize low-melting-point glass powder, and then the main sintering block and the low-melting-point glass powder are mixed and dispersed to obtain the required barium niobate system microwave dielectric ceramic material. The dielectric constant of the microwave dielectric ceramic material reaches 33-36, f*Q at 25 DEG C is larger than 80000, the frequency temperature coefficient calculated by testing the resonant frequencies f at -40 DEG C, 25 DEG C and 110 DEGC is low and is only -5 ppm/DEG C to 5 ppm/DEG C, and the performance of the microwave dielectric ceramic material meets the requirements of microwave dielectric ceramic devices. Meanwhile, the material also has relatively good dielectric properties in a millimeter wave frequency band, and the method can be used for producing ceramic devices such as filters and resonators.

The invention belongs to the technical field of microwave dielectric ceramic materials, and particularly relates to a two-phase composite microwave dielectric ceramic material. The two-phase compositemicrowave dielectric ceramic material is prepared from Ba(Zn<1/3>Nb<2/3>)O<3>, MgTiO<3> and a selectively-added oxide additive through solid-phase synthesis; the obtained microwave dielectric ceramicmaterial can be sintered into ceramic at a sintering temperature of 1320 to 1370 DEG C; the dielectric constant of a test wafer reaches 30-35, the value of f*Q at 25 DEG C is larger than 60000, a frequency temperature coefficient calculated by testing resonant frequencies f at -40 DEG C, 25 DEG C and 110 DEG C is low and ranges from -5 ppm/DEG C to 5 ppm/DEG C, and the performance of the test wafer meets the requirements on microwave dielectric ceramic devices; meanwhile, the material also has relatively good dielectric properties in a millimeter wave frequency band; and the material can be used for producing ceramic devices such as filters and resonators.

The invention provides a temperature compensation type surface acoustic wave device and a manufacturing method thereof. The manufacturing method comprises the following steps: providing a piezoelectric material substrate; coating a first photoresist on the piezoelectric material substrate, exposing and developing the first photoresist, and defining an IDT metal layer semi-buried gully pattern; etching the piezoelectric material substrate to form an IDT metal filling trench corresponding to the IDT metal layer semi-buried trench pattern, and removing the first photoresist; depositing metal on the etched piezoelectric material substrate to form an IDT metal layer, and enabling the IDT metal layer to fill the IDT metal filling trench and overflow the IDT metal filling trench; coating a secondphotoresist on the IDT metal layer, exposing and developing the second photoresist, and defining an IDT pattern; etching the IDT metal layer to form an IDT metal finger strip structure correspondingto the IDT pattern, and removing the second photoresist; and depositing a dielectric material on the piezoelectric material substrate and the IDT metal finger strip structure to form a dielectric layer.

The invention provides a Lamb wave resonator with a POI structure. The Lamb wave resonator may include: a substrate of high acoustic velocity material; a piezoelectric layer located above the substrate made of the high-sound-velocity material, wherein a first interdigital transducer and a second interdigital transducer are arranged on the upper surface and the lower surface of the piezoelectric layer respectively, and interdigital electrodes of the first interdigital transducer and the second interdigital transducer are opposite to each other in the stacking direction across the piezoelectric layer. The first interdigital transducer and the second interdigital transducer have same electrode width, electrode thickness, electrode pitch, duty cycle p, and excitation sound wave wavelength lambda, where the duty cycle p = electrode width/(electrode width + electrode pitch), and where the duty cycle p is set to 0.2-0.5.

The invention relates to a surface acoustic wave (SAW) device having high electromechanical coupling coefficient and high centre frequency. The SAW device adopts a diamond film as the substrate, and adopts an AlN and ZnO film periodically stacked structure (AlN/ZnO)<N> as the piezoelectric layer; the period N of the stacked structure is 2-5; and the thickness ratio of R<h> of an AlN film to a ZnO film is 0.2-5. According to the SAW device disclosed by the invention, respective advantages and disadvantages of two piezoelectric materials including AlN and ZnO are considered; the cooperative effect of the two is utilized, so that the comprehensive performance of the device is improved; under the same interdigital width, compared with the ZnO and AlN double-piezoelectric-layer structure, the structure has the advantages that: the electromechanical coupling coefficient of the device can be maximally increased by two times; furthermore, the centre frequency cannot be reduced; simultaneously, the temperature stability of the device is also improved; the frequency temperature coefficient is reduced; in addition, when the SAW device is designed, more adjustable parameters of the structure exist; the performance parameter adjusting range of the device is relatively wide; and thus, the application field of the device is enlarged.

The invention discloses microwave dielectric ceramics and a preparation process thereof, belonging to the technical field of microwave dielectric materials and manufacture thereof. The microwave dielectric ceramics comprises carbonate, oxide and Na, Gd, Dy, Er, Lu and Ti organic matters, and has a chemical formula of Na0.5Re4.5Ti4O15, wherein Re=Gd, Dy, Er and Lu. The invention provides a novel rare-earth-containing microwave dielectric material, and the selection range of a microwave dielectric application material is enlarged; and aiming at the microwave dielectric ceramics, the invention provides a novel matched process, namely, the microwave dielectric ceramics with better ceramic formation is obtained by combination of a process of preparing a powder material by adopting a sol-gel process and a process of preparing the ceramics by adopting a solid-phase reaction process.

The invention discloses a quartz resonator based on piezoelectric film transduction, and the quartz resonator comprises a substrate, an acoustic mirror, a piezoelectric film transduction layer, a quartz resonance main body layer, a first electrode and a second electrode, wherein the electromechanical coupling coefficient of the piezoelectric film transduction layer is greater than that of the quartz resonance main body layer. The quartz resonator has the characteristics of high Q value, high electromechanical coupling coefficient, high frequency stability, simple manufacturing and the like.

The invention provides a Lamb wave resonator with a POI structure. The Lamb wave resonator may include: a substrate of high acoustic velocity material; a piezoelectric layer which is located above thesubstrate made of the high-sound-velocity material, wherein a first interdigital transducer and a second interdigital transducer are arranged on the upper surface and the lower surface of the piezoelectric layer respectively, and interdigital electrodes of the first interdigital transducer and the second interdigital transducer are opposite to each other in the stacking direction across the piezoelectric layer, and have the same electrode width, electrode thickness, electrode spacing, duty ratio eta and excitation sound wave wavelength lambda, wherein the duty ratio eta = electrode width/(electrode width + electrode spacing), the material of the piezoelectric layer is YX-LiNbO3 with a cut angle theta, and the values of the cut angle theta and the duty ratio eta are 30 degrees < = theta <= 60 degrees respectively; and eta is equal to 0.2, 0.4 to 0.6 or 0.8 to 0.9.

The invention discloses a surface acoustic wave filter with high temperature stability and a preparation method and application thereof. The surface acoustic wave filter comprises a piezoelectric substrate which is provided with at least one plane; an interdigital transducer electrode, wherein the interdigital transducer electrode is fixedly arranged on the plane of the piezoelectric substrate; aninsulating protective layer provided with two opposite surfaces, wherein one surface of the insulating protective layer is laminated and combined on the plane of the piezoelectric substrate and covers the interdigital transducer electrode; and a plurality of bulges which are distributed at intervals are formed on the other surface. The surface acoustic wave filter has the advantages of low frequency temperature coefficient, low Rayleigh wave parasitic response phenomenon, stable working performance, long service life and the like. Moreover, the preparation method is controllable in process conditions, and can effectively ensure that the prepared surface acoustic wave filter with high temperature stability is stable in performance, high in yield and low in cost.