摘要:
A dielectric ceramic composition is disclosed comprising lead magnesium niobate and strontium titanate, barium titanate or a combination thereof. Dopants such as Ta, La, Y, Eu, Nd, Sm, Gd, W, Si, Zr and Sb may also be included in the composition. The lead magnesium niobate with strontium titanate and/or barium titanate composition has been found to possess extremely favorable properties such as high dielectric constant, low dielectric loss, high breakdown strength, low field-induced strain, high electrical resistivity and exceptionally high energy storage capacity. A process is also disclosed for the production of dielectric ceramic materials which includes the use of hot isostatic pressing in an oxygen-containing atmosphere. The disclosed dielectric compositions are useful in capacitors for many applications, including medical devices such as defibrillators and pacemakers.
摘要:
A method of producing an LTCC substrate having improved cavity bondability is disclosed that involves providing a stack of green ceramic tape sheets having a cavity, placing a template having an opening corresponding to the cavity over the stack, placing a stretchable sheet of material coated with graphite or zinc stearate over the template, isostatically laminating the stack to produce an LTCC substrate having a cavity, and removing the template and sheet of stretchable material from the stack.
摘要:
A phased array includes a first plurality of radiators having a first polarization and a second plurality of radiators having a second polarization, different from said first polarization. The phased array is constructed such that radiating patterns of the first and second plurality of radiators are congruent. The radiators are constructed so that they radiating apertures thereof can occupy virtually the same space, i.e., the spacing of the radiating elements is less than a wavelength. Other features provided allow this compactness to be achieved. Impedance matching features are integrated into the radiators themselves. The elevation assemblies of the radiators are mated together, and then are coupled across to their respective azimuth assemblies. Two azimuth assemblies for either type of polarization may be provided when monopulse operation is required. Assemblies for both polarizations transmit sequentially, but receive simultaneously, thus allowing a complete polarization matrix to be collected with two pulse transmissions.
摘要:
This invention relates to new ceramic electrostrictive compositions having superior electrical properties, a process for the preparation of the new electrostrictive compositions and applications for the new compositions. Specifically, a solid solution composition of lead magnesium niobate-lead titanate--(barium titanate or stronium titanate) has exhibited desirable electrostrictive properties. This composition shows a diminished dependence of dielectric constant on temperature.