The Proportioning of Shielded Circuits for Minimum High-Frequency Attenuation

S I N C E the very beginning of mathematics, problems of maximizing and minimizing have possessed a marked fascination. The Greeks were successful in solving a few geometric problems of this character. Later, algebra was found to be another method of attack. Finally, the powerful methods of the calculus became available for the determination of maxima and minima in manifold variety. The reasons for the continued interest in such problems are not hard to find. It is but natural to seek the ideal, and here, at least, is one phase of mankind's search for perfection in which a goodly measure of success may be achieved. In addition, a knowledge of the optimum dimensioning of things, or of the optimum relations between things, frequently holds much practical significance. It is mainly with problems of maxima and minima that this paper is concerned. These problems have to do with transmission circuits which are surrounded by individual shields. Recent literature 2 has pointed out that circuits of this type have properties which render them especially suitable for the transmission of broad bands of frequencies. Such circuits are also finding application as "lead-ins" to connect radio antennas with transmitting or receiving apparatus. 3 , 4 1