Abstract: A ceramic-polymer composite material such as part of a microelectronics package is formed of a ceramic mixture of aluminum nitride and boron nitride, and a low-loss polymeric material. The amount of aluminum nitride is preferably from about 50 to about 90 weight percent of the ceramic mixture, but the relative amounts of the two ceramics may be adjusted to achieve thermal expansion and thermal conductivity properties required for a particular application. A mixture of the ceramics and uncured thermosetting polymeric resin is formed, pressed into the shape of the microelectronics base and/or lid, and heated (either concurrently or subsequently) to compress the mixture and cure the polymer.

Abstract: Methods of fabricating a porous ceramic composite having voltage-variable dielectric properties. The composite is made as follows. A polycrystalline ferroelectric powder, which is a ferroelectric perovskite such as barium strontium titanate, for example, is provided. The powder, a binder and a filler are then mixed in water to form a slurry. The powder-binder-filler slurry is then dried. The dried powder-binder-filler slurry is granulated. The granulated powder-binder-filler is pressed into a die. The binder and filler are then burned out to form a fragile porous ash-like structure. The porous structure is then sintered to form porous ceramic parts. The porous ceramic parts are then machined tiles. The machined porous tiles may then be tested for microwave properties. Fabrication methods for producing porous ferroelectric ceramic-polymer composite tiles or subaperture blanks and continuous transverse stub electronically scanned antenna plates or subapertures are also disclosed.

Abstract: The present invention relates to a low temperature method of preparing a compound of the formula:ABO.sub.3whereinA=Ba, Sr, Ca and Pb; andB=Ti, Zr and Hf,by(a) reacting a B-alkoxide, with a predetermined amount of aqueous A-hydroxide,(b) heating the reaction mixture to an initial temperature of 100.degree. C.-250.degree. C. at 1-40 atmospheres of pressure;(c) cooling the reaction mixture and thereafter, heating it to a subsequent temperature of approximately 40.degree. C. to 60.degree. C.;(d) dialyzing the cooled reaction product and recovering the tenate.