A silica glass for a radio-frequency device has an OH group concentration being less than or equal to 300 wtppm; an FQ value being higher than or equal to 90,000 GHz at a frequency of higher than or equal to 25 GHz and lower than or equal to 30 GHz; and a slope being greater than or equal to 1,000 in a case where the FQ value is approximated as a linear function of the frequency in a frequency band of higher than or equal to 20 GHz and lower than or equal to 100 GHz.

A The heating element structure includes: a conductive metal substrate; a heating layer spaced apart from the conductive metal substrate and configured to generate heat in response to an electrical signal; electrodes in contact with the heating layer and configured to provide the electrical signal to the heating layer; and a first insulating layer on the conductive metal substrate, the first insulating layer comprising a first matrix material and a particle, wherein a difference between a coefficient of thermal expansion (CTE) of the first matrix material and a coefficient of thermal expansion of the particle is about 410.sup.6 per Kelvin or less.

A The heating element structure includes: a conductive metal substrate; a heating layer spaced apart from the conductive metal substrate and configured to generate heat in response to an electrical signal; electrodes in contact with the heating layer and configured to provide the electrical signal to the heating layer; and a first insulating layer on the conductive metal substrate, the first insulating layer comprising a first matrix material and a particle, wherein a difference between a coefficient of thermal expansion (CTE) of the first matrix material and a coefficient of thermal expansion of the particle is about 410.sup.6 per Kelvin or less.

An article including a glass having that includes SiO.sub.2, Al.sub.2O.sub.3, and B.sub.2O.sub.3 and least one of Li.sub.2O, Na.sub.2O, K.sub.2O, MgO, CaO, SrO, BaO, SnO.sub.2, ZnO, La.sub.2O.sub.3, F, and Fe.sub.2O.sub.3, wherein the glass includes a dielectric constant of about 10 or less and/or a loss tangent of about 0.01 or less, both as measured with signals at 10 GHz.

A glass substrate for a high-frequency device, which contains SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of alkaline earth metal oxides in the range of 0.1-13% in terms of mole percent on the basis of oxides, wherein at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A glass substrate for a high-frequency device, which contains SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of alkaline earth metal oxides in the range of 0.1-13% in terms of mole percent on the basis of oxides, wherein at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A low K value, high Q value, low firing dielectric material and method of forming a fired dielectric material. The dielectric material can be fired below 950 C. or below 1100 C., has a K value of less than about 8 at 10-30 GHz and a Q value of greater than 500 or greater than 1000 at 10-30 GHz. The dielectric material includes, before firing a solids portion including 10-95 wt % or 10-99 wt % silica powder and 5-90 wt % or 1-90 wt % glass component. The glass component includes 50-90 mole % SiO.sub.2, 5-35 mole % or 0.1-35 mole % B.sub.2O.sub.3, 0.1-10 mole % or 0.1-25 mole % Al.sub.2O.sub.3, 0.1-10 mole % K.sub.2O, 0.1-10 mole % Na.sub.2O, 0.1-20 mole % Li.sub.2O, 0.1-30 mole % F. The total amount of Li.sub.2O+Na.sub.2O+K.sub.2O is 0.1-30 mole % of the glass component. The silica powder can be amorphous or crystalline.

A low K value, high Q value, low firing dielectric material and method of forming a fired dielectric material. The dielectric material can be fired below 950 C. or below 1100 C., has a K value of less than about 8 at 10-30 GHz and a Q value of greater than 500 or greater than 1000 at 10-30 GHz. The dielectric material includes, before firing a solids portion including 10-95 wt % or 10-99 wt % silica powder and 5-90 wt % or 1-90 wt % glass component. The glass component includes 50-90 mole % SiO.sub.2, 5-35 mole % or 0.1-35 mole % B.sub.2O.sub.3, 0.1-10 mole % or 0.1-25 mole % Al.sub.2O.sub.3, 0.1-10 mole % K.sub.2O, 0.1-10 mole % Na.sub.2O, 0.1-20 mole % Li.sub.2O, 0.1-30 mole % F. The total amount of Li.sub.2O+Na.sub.2O+K.sub.2O is 0.1-30 mole % of the glass component. The silica powder can be amorphous or crystalline.

Glass compositions and glass fibers having low dielectric constants and low dissipation factors that may be suitable for use in electronic applications and articles are disclosed. The glass fibers and compositions of the present invention may include between 45.0 to 58.0 weight percent SiO.sub.2; greater than 18.0 weight percent B.sub.2O.sub.3 and no more than 26.0 weight percent B.sub.2O.sub.3; greater than 16.0 weight percent Al.sub.2O.sub.3 and no more than 23.0 weight percent Al.sub.2O.sub.3; between 0.25 to 12.0 weight percent P.sub.2O.sub.5; greater than 0.25 weight percent CaO and less than 5.00 weight percent CaO; less than 4.50 weight percent MgO; greater than 0.25 weight percent CaO+MgO and less than 5.00 weight percent CaO+MgO; less than 0.80 weight percent Fe.sub.2O.sub.3; and less than 0.50 weight percent TiO.sub.2. Further, the glass composition has a glass viscosity of 1000 poise at a temperature greater than 1350 degrees Celsius.

Glass compositions and glass fibers having low dielectric constants and low dissipation factors that may be suitable for use in electronic applications and articles are disclosed. The glass fibers and compositions of the present invention may include between 45.0 to 58.0 weight percent SiO.sub.2; greater than 18.0 weight percent B.sub.2O.sub.3 and no more than 26.0 weight percent B.sub.2O.sub.3; greater than 16.0 weight percent Al.sub.2O.sub.3 and no more than 23.0 weight percent Al.sub.2O.sub.3; between 0.25 to 12.0 weight percent P.sub.2O.sub.5; greater than 0.25 weight percent CaO and less than 5.00 weight percent CaO; less than 4.50 weight percent MgO; greater than 0.25 weight percent CaO+MgO and less than 5.00 weight percent CaO+MgO; less than 0.80 weight percent Fe.sub.2O.sub.3; and less than 0.50 weight percent TiO.sub.2. Further, the glass composition has a glass viscosity of 1000 poise at a temperature greater than 1350 degrees Celsius.