GB986431A - A strip transmission line attenuator - Google Patents

Abstract

986,431. Strip-line attenuators. SANDERS ASSOCIATES Inc. Sept. 29, 1961 [Nov. 17, 1960], No. 35333/61. Heading H1W. An adjustable T or # attenuator comprises relatively movable resistive and conductive sections of a strip transmission line. The line is of the type comprising two outer ground conductors and a central line conductor. In the T attenuator shown in Figs. 2, 3, the outer conductors are formed by a pair of recessed metal blocks 24, 26 and portions of the inner conductor are supported in sliding engagement with each other on the inner surfaces of dielectric blocks 32, 34. The inner conductor configuration comprises input and output conductive portions 18, 23, connected to coaxial terminals on the lower metal block, and a shunt resistive portion 21 conductively connected to this metal block, all these portions being mounted on the lower dielectric block 34. Series resistive portions 19, 22 and conductive bridge portion 20 are mounted upon the upper dielectric block 32, the arrangement being such that relative movement of the dielectric blocks causes the amount of shunt resistance 21 effectively in circuit to vary inversely with the amount of the series resistances 19, 22 effectively in circuit. The dielectric blocks are urged towards each other by a spring 48 made of dielectric material. In an alternative configuration for a # attenuator (Fig. 4) input and output conductive portions 50, 62, series resistive portions 52, 60 and shunt resistive portion 56 are all mounted on the lower dielectric block. A conductive bridging portion 64 is mounted on the upper dielectric block. In a modification of the # attenuator (Fig. 5A), a variable portion of a resistive element 82 mounted on the upper dielectric block is intercepted by conductors 66, 74. The # configuration comprises a central (series) portion 70 of element 82 and two outer (shunt) portions 68, 72.