Abstract: A circuit board with a cooling device having channels through which a cooling agent flows, the circuit board being comprised of at least three united layers including an inner layer wherein the channels are formed.

Abstract: For the connection of an electro-optical chip (5) to a substrate (4), optical and electrical connecting elements (1, 8) are produced on a flexible interconnect member (2) and connected, using a film bonding process previously known only for purely electrical connections, both with connector elements of the chip and with connector paths or optical waveguides (3) on the substrate. If the optical connecting elements (1) are positioned physically between the electrical connecting elements (8), they are secured and located by the soldering connections produced on both sides of the electrical connecting elements. In addition to electrical test adapter connectors, optical test loops which link optical inputs and outputs with each other and which are removed during a later stamping process can also be provided on the flexible interconnect member (2).

Abstract: Coaxial signal lines of rectangular cross-section are fabricated for use in integrated high- and ultra-high-frequency circuits, thereby eliminating crosstalk. A photolithographic film not only assists in the formations of metallic conductive areas, but also remains between those conductive areas as the dielectric material between inner and outer conductors of a fully shielded rectangular coaxial cable. The coaxial cable is formed in a process which comprises various photoprocessing, electrodeposition, chemical deposition and chemical etching steps, but which avoids mechanical surfacing to remove insulating material from adjacent portions of the conductive walls of the outer conductor of the coaxial cable.

Abstract: An article of manufacture useful as the base for an electronic circuit board is a substrate with an enamel layer having a heterogeneous structure containing at least two different phases obtained by applying a homogeneous, alkali-containing enamel powder to the substrate followed by heating at 850.degree. C. to 1,000.degree. C. wherein the enamel power has the composition as follows:______________________________________ Si.sub.O2 40-50% by weight Al.sub.2 O.sub.3 8-15% by weight Na.sub.2 O + K.sub.2 O 4-16% by weight CaO + BaO 25-35% by weight MgO 0-3% by weight B.sub.2 O.sub.3 0-10% by weight.