Full band attenuators are waveguide based attenuators of four types: fixed, level setting, direct reading and programmable. These attenuators are offered to cover the frequency range of 18 to 140 GHz. Fixed and level setting attenuators are constructed with an E-plane resistive insert in the rectangular waveguide.The standard attenuation values for fixed attenuators are 3, 6, 10, 20 and 30 dB, and the attenuation range of level setting attenuators is adjustable from 0 to 30 dB via a micrometer. Fixed and level setting attenuators are typically used for signal attenuation when accuracy is not a focus. Direct reading and programmable attenuators are constructed with a precision, resistive rotary vane in a circular waveguide. The operating mode of the attenuators is the circular waveguide, TE11 mode. Unlike fixed and level setting attenuators, the attenuation value and phase shift of these attenuators are independent of the frequency. The direct reading attenuator is ideal in waveguide systems when a broadband direct reading of attenuation or a standard for system calibration and instrumentation is required. The programmable attenuator is designed for both manual and computerized operations. While the toggle switch and LED indicator on the front panel are used for manual operations, an IEEE-488 or RS-232 interface on the back panel is used for automatic controls. The programmable attenuator is ideal in ATE systems where the attenuation is controlled remotely via a computer interface.