Microwave Printed Circuits - A Historical Survey

The microwave printed circuit, as described in this paper, is an extension of the well-known technique which is of such importance in the lower frequency regions, where lumped element circuits are practical. This new circuit possesses all of the virtues of other printed circuits, such as light weight, cheapness, ease of manufacture, miniaturization, etc., along with the ability to be used at frequencies as high as 10,000 mc. The basis of the new technique is the planar or "flat strip" coaxial transmission system which was developed during World War II but which has remained unpublished and relatively unknown in the postwar period; and for which an adequate theoretical analysis had not been available.