A line of multi-hole broadwall directional couplers covers 2.6 to 40 GHz in standard waveguide sizes. Examples include a WR-28 model, which spans 26.5 to 40 GHz; a WR-42 model, which covers 18 to 26.5 GHz; and a WR-284 model, which operates from 2.60 to 3.95 GHz. All models offer a primaryline VSWR of 1.10:1 maximum and secondary-line VSWR of 1.15:1 maximum. Coupling values are 10, 20, 30, 40, or 50 dB (1 dB). Minimum directivity is specified at 35 dB. The couplers' electrical characteristics, which include high directivity and repeatable coupling flatness, are achieved using a precise machined coupling hole pattern and a precision load in the secondary arm. Non-standard configurations or selected electrical parameters are available on request. Various flange types are available.