Abstract: Step attenuators wherein a number of individual attenuators are connected in series, with a switch across each individual attenuator, are well known. By opening and closing particular combinations of the switches, any one of a number of different values of attenuation may be selected. Each individual attenuator has in the past, as well as in the present invention, had a characteristic impedance equal to the impedance of both the signal generator (which feeds the input of the step attenuator) and the load (connected across the output of the step attenuator). However, the switches for selecting the individual attenuators may have substantial resistance especially where solid state switching diodes or mercury wetted reed relays are employed. The latter type switches display resistances caused by skin effect at highter frequencies. This causes inaccuracies of the attenuation steps due to mismatch, in prior art systems of the type described above.

Abstract: The invention relates to a card-type attenuator having a flat insertion loss from DC to 2 GHz or higher. A rectangular card has two ground conductors extending along its longitudinal side edges and an inner conductor extending along a first face of the card midway between said ground conductors. The outer conductor comprises two main parts: First, a metal trough into which the card is placed with the two ground conductors, and secondly, an inverted U-shaped metallic spring which has its free ends pressing against the ground conductors respectively to hold them firmly in the trough. The inner conductor is accurately positioned a distance from the bottom of the trough which is small compared to the distance that the U-shaped spring is above the inner conductor. Hence, most of the electromagnetic field exists between the inner conductor and the bottom of the trough. Accordingly, the exact size and shape of the U-shaped spring is not critical.

Abstract: The present invention relates to a detent mechanism for a rotatable body to bias the body in any of a multiplicity of predetermined angular positions. The body has a projecting element of polygon shape, extending from its rear end. The element defines a cavity in it. A projection extends inwardly from the wall of the cavity. The projection cooperates with a stop to limit the angular rotation of the body. The device is designed to permit different polygons to be used so that the number of angular positions at which the body stops may be changed. The detent mechanism is shown in conjunction with a microwave drum attenuator since it is desirable, in such an attenuator to reduce undesirable forces on the drum attenuator.