4841 results about "Dielectric loss" patented technology

A polycrystalline chemical vapour deposited (CVD) diamond wafer comprising: a largest linear dimension equal to or greater than 70 mm; a thickness equal to or greater than 1.3 mm; and one or both of the following characteristics measured at room temperature (nominally 298 K) over at least a central area of the polycrystalline CVD diamond wafer, said central area being circular, centred on a central point of the polycrystalline CVD diamond wafer, and having a diameter of at least 70% of the largest linear dimension of the polycrystalline CVD diamond wafer: an absorption coefficient ≦0.2 cm⁻¹ at 10.6 μm; and a dielectric loss coefficient at 145 GHz, of tan δ≦2×10⁻⁴.

An efficient, low-loss, low sidelobe, high dynamic range phased-array radar antenna system is disclosed that uses metamaterials, which are manmade composite materials having a negative index of refraction, to create a biconcave lens architecture (instead of the aforementioned biconvex lens) for focusing the microwaves transmitted by the antenna. Accordingly, the sidelobes of the antenna are reduced. Attenuation across microstrip transmission lines may be reduced by using low loss transmission lines that are suspended above a ground plane a predetermined distance in a way such they are not in contact with a solid substrate. By suspending the microstrip transmission lines in this manner, dielectric signal loss is reduced significantly, thus resulting in a less-attenuated signal at its destination.

The invention provides electronic parts which comprise a composite dielectric layer composed of an organic insulating material and a dielectric ceramic powder having a larger relative dielectric constant than the organic insulating material, and which also comprise conductive element sections forming inductor elements, etc., wherein the organic insulating material comprises a cured resin obtained by curing reaction of an epoxy resin with an active ester compound obtained by reaction between a compound with two or more carboxyl groups and a compound with a phenolic hydroxyl group. The dielectric ceramic powders of the described electronic parts have larger relative dielectric constants than the organic insulating materials, and the organic insulating materials have low dielectric loss tangents. It is possible to adequately reduce time-dependent dielectric constant changes in the high-frequency range of 100 MHz and above even with prolonged use at high temperatures of 100° C. and higher, while it is also possible to satisfactorily prevent deformation and other damage to the electronic parts during their handling.

To provide a thin metal base circuit board which can be not only installed on a flat portion but also closely attached to a side or bottom surface of a case or to a stepped or curved portion and which is excellent in heat dissipation performance, electrical insulating performance and flexibility; a process for its production; and a hybrid integrated circuit, an LED module and a bright, ultra-long-life LED light source employing it.

A metal base circuit board having insulating layers and conductive circuits or metal foils alternately laminated, characterized in that the thickness of each conductive circuit or metal foil is from 5 μm to 450 μm, each insulating layer is made of a cured product of a resin composition comprising an inorganic filler and a thermosetting resin, and the thickness of each insulating layer is from 9 μm to 300 μm; and a hybrid circuit board employing it. The metal base circuit board wherein a coverlay is provided, and a layer having a magnetic loss or a layer having a dielectric loss is laminated on the surface of the coverlay. A LED light source unit having at least one light-emitting diode (LED) mounted on the conductive circuit.

The invention relates to a composite material, a high-frequency circuit substrate therefrom and a manufacture method thereof. The composite material comprises thermoset mixture, glass fiber cloth, power filler, a fire retardant and a curing initiator, wherein the thermoset mixture comprises more than one kind of vinyl liquid resin and polyphenyl ether resin; the molecular weight of the vinyl liquid resin is below 10000, and the vinyl liquid resin is provided with a polar functional group; the molecular weight of the polyphenyl ether resin is less than 5000, and the molecular tail end of the polyphenyl ether resin is provided with unsaturated double bonds. The high-frequency circuit substrate manufactured with the composite material comprises multiple layers of semi-solidified sheets and copper foils, wherein the semi-solidified sheets are mutually overlaid, and the copper foils are respectively pressed on two sides. The composite material disclosed by the invention causes the semi-solidified sheets to be easily manufactured and have high adhesive bonding force with the copper foils. The high-frequency circuit substrate manufactured by the material has the advantages of low dielectric constant, low dielectric loss angle tangent, good heat resistance and simple technical operation. Thus, the composite material disclosed by the invention is suitable for manufacturing the circuit substrate of the high-frequency electronic equipment.

A conductive rubber roller 10 having a conductive rubber layer 1, containing chloroprene rubber, which composes an outermost layer thereof. When an alternating current is applied to the conductive rubber roller 10 at a voltage of five and a frequency of 100 Hertz, a dielectric loss tangent is 0.1 to 1.8.

A multilayer film useful for capacitive applications comprises a high energy density layer and a dielectric blocking layer. In some embodiments, a conducting film is located between the high energy density layer and the blocking layer. The high energy density layer may be a fluoropolymer, such as a polymer or copolymer of poly-1,1-difluoroethene or a derivative thereof. The multilayer film may have high energy density (for example,. >8 J/cm³) and low dielectric loss, for example less than 2%, and preferably less than 1%.

The invention provides halogen-free resin composition, and a copper clad laminate and a printed circuit board applying the halogen-free resin composition. The halogen-free resin composition comprises, by weight, (A) 100 parts of epoxy resin, (B) 1 part -100 parts of benzoxazine resin, (C) 1part -100 parts of styrene maleic anhydride, (D) 0.5 part -30 parts of amine curing agents, and (E) 5-150 parts of halogen-free flame retardants. By means of the specified constituents and ration, the halogen-free resin composition achieves the purposes of low dielectric constant, low dielectric loss, high heat resistance, and high flame resistance, can be manufactured into semi-solidified rubber pieces or resin films, and then achieves the purposes of being applied to the copper clad laminate and the printed circuit board.

The invention provides a method for preparing high dielectric constant polymer-based nano composite material. The method comprises the following steps: performing electrostatic spinning on a polymer matrix solution and simultaneously performing electrostatic spraying on a filler particle suspension; simultaneously receiving the products of the electrostatic spinning and the electrostatic spraying through a common receiving device to obtain a composite fiber membrane; and finally obtaining the high dielectric constant polymer-based nano composite material with filler particles uniformly dispersed after the composite fiber membrane is processed through a hot-pressing processing technique. The composite material prepared by the invention has the characteristics of high dielectric constant, low dielectric loss and the like; and at the same time the dielectric constant of the composite material can be adjusted through adjusting the content of the filler particles in the polymer matrix. The invention has the advantages of simple process, convenient operation and little environment pollution, can well solve the problem that the filler particles is uniformly dispersed in the polymer matrix, and is expected to the microelectronic industry as dielectric material and the like for preparing embedded capacitors.

The invention relates to a low dielectric material. The low dielectric material includes, by weight, 40-80 parts of polyphenyl ether with the number average molecular weight Mn of 1000-4000, the weight average molecular weight Mw of 1000-7000 and the Mw/Mn ratio of 1.0-1.8, 5-30 parts of bimaleimide and 5-30 parts of a polymer additive, and the Dk value and the Df value of the low dielectric material are 3.75-4.0 and 0.0025-0.0045 respectively. The low dielectric material can be applied to semi-cured films or circuit substrate insulating layers, and has the characteristics of high Tg, low thermal expansion coefficient, low water absorption rate, and excellent dielectric properties like dielectric constant (Dk) and dielectric loss (Df).

Disclosed herein is a composite material comprising a relaxor ferroelectric material and a hydrazine-reduced graphene oxide, wherein the weight ratio of the composite material to the hydrazine-reduced graphene oxide is 9:1 to 200:1. The composite materials have high dielectric permittivity and low dielectric losses and can be used to manufacture various high dielectric permittivity components.

The invention has for its object to provide a composite dielectric material having any desired dielectric constant selectable from a relatively wide range in a high-frequency band and a low dielectric loss tangent, and a film, substrate, electronic part or molded or otherwise formed article using the same. To accomplish this object, there is provided a composite dielectric material composition comprising a heat-resistant, low-dielectric polymeric material that is a resin composition comprising one or two or more resins having a weight-average absolute molecular weight of at least 1,000, wherein the sum of carbon atoms and hydrogen atoms in said composition is at least 99%, and some or all resin molecules have a chemical bond therebetween, and a filler. A film, substrate, electronic part or molded or otherwise formed article is obtained using this composition.

The invention discloses a thermosetting resin composition, which is characterized by comprising the following components in part by weight: 8 to 80 parts of allyl modified bismaleimide resin prepolymer, 15 to 60 parts of cyanate resin and 5 to 40 parts of halogen-free epoxy resin, wherein the allyl modified bismaleimide resin prepolymer is prepared by reacting bismaleimide resin with an allylcompound at the temperature of between 110 and 160DEG C for 20 to 100 minutes, and a weight ratio of the bismaleimide resin to the allylcompound is 100:(30-120). The composition can be used for preparing a prepreg and a laminated board. The composition and the laminated board have excellent humidity resistance, high heat resistance, low water absorption rate, high modulus, lower dielectric constant and dielectric loss, and good processing toughness, and can realize halogen-free flame retardancy.

Provided is a pressure-sensitive adhesive sheet for optical use which less suffers from a misoperation-causing change in capacitance upon application to an optical member.

The pressure-sensitive adhesive sheet for optical use includes a pressure-sensitive adhesive layer and has a dielectric constant of from 2 to 8 at a frequency of 1 MHz and a dielectric loss tangent of more than 0 and 0.2 or less at a frequency of 1 MHz. The pressure-sensitive adhesive sheet for optical use preferably has a dielectric constant at a frequency of 1.0×10⁶ Hz being 60% or more of that at a frequency of 1.0×10⁴ Hz. In addition, the pressure-sensitive adhesive sheet for optical use preferably has an absolute value of difference between the dielectric loss tangent at a frequency of 1.0×10⁶ Hz and that at a frequency of 1.0×10⁴ Hz of 0.15 or less.

The invention relates to a monitoring system for power transmission and transforming equipment, in particular to a capacitive equipment dielectric loss angle online monitoring system. The system is characterized by at least comprising a microprocessor, a leakage current signal acquisition module, a GPS synchronization module, a wireless communication module, an A/D sampling unit, and a frequency measurement sampling unit; in structure, a centralized management mode is used, a wireless data transmission technology and an Internet network technology are applied, and a layered distributed structure is achieved; according to the functional requirements, the invention divides the system into a monitoring layer, a control layer and an information layer. The manufacturer and operating management department (client) can visit the system in different places by only installing browser software and thus easily achieve remote maintenance and monitoring.

Examples of the present invention include high electric energy density polymer film capacitors with high dielectric constant, low dielectric dissipation tangent, and low leakage current in a broad temperature range. More particularly, examples include a polymer film capacitor in which the dielectric layer comprise a copolymer of a first monomer (such as tetrafluoroethylene) and a second polar monomer. The second monomer component may be selected from vinylidene fluoride, trifluoroethylene or their mixtures, and optionally other monomers may be included to adjust the mechanical performance. The capacitors can be made by winding metallized films, plain films with metal foils, or hybrid construction where the films comprise the new compositions. The capacitors can be used in DC bus capacitors and energy storage capacitors in pulsed power systems.

Examples of the present invention relate generally to high electric energy density polymer film capacitors with high charge-discharge efficiency and fast discharge speed. For example, a high energy density polymer capacitor may be fabricated using a polymer blend comprising one or more high dielectric constant PVDF-based polymers (including homopolymers, copolymers and/or terpolymers) and one or more other polymer with low dielectric loss and high volume resistivity compared to the one or more PVDF-based polymers. An example film capacitor may comprise a high temperature fluoropolymer with dielectric loss lower than 0.2% and good film manufacturability. Polymer films can be stretched and orientated at least in one direction to make thinner films with improved performance. Film capacitors can be made by winding metallized films, plain films with metal foils, or using a hybrid construction where the dielectric films comprise the new compositions. Capacitors can also have a multilayer construction where the films are metallized.

The invention provides a halogen-free resin composition which comprises (A) 100 parts of cyanate ester resin, (B) 5-50 parts of styrene maleic anhydride, (C), 5-100 parts of polyphenyl ether resin, (D) 5-100 parts of maleimide resin, (E) 10-150 parts of nitrogenous compound, and (F) 10-1000 parts of inorganic filler. As the composition comprises components in special proportion, the halogen-free resin composition is low in dielectric constant, low in dielectric loss, high in heat resistance and high in flame resistance. The halogen-free resin composition can be prepared as a semi-cured film or a resin film, so that the composition can be applied to a copper foil substrate and a printed circuit board.

The invention discloses a halogen-free resin composition and a method for preparing a copper-clad plate from the halogen-free resin composition. Based on the total weight part of solid ingredients of the halogen-free resin composition, the halogen-free resin composition comprises, by weight, 5 to 50 parts of reaction-type allylphenoxycyclotriphosphazene or vinylphenoxycyclotriphosphazene, 15 to 85 parts of a thermosetting resin, 1 to 35 parts of a crosslinking curing agent, 0 to 5 parts of a crosslinking curing accelerator and 0 to 100 parts of a filling material. Through introduction of reaction-type allylphenoxycyclotriphosphazene or vinylphenoxycyclotriphosphazene having very low water absorbency into the thermosetting resin, the halogen-free resin composition can satisfy halogen-free flame-retardation requirements, improve system electrical properties, and realize non-halogenation of a high-frequency high-speed substrate material. The copper-clad plate prepared from the halogen-free resin composition satisfies halogen-free requirements, has excellent heat resistance and moisture resistance and has a low dielectric loss.