QuinStar products QDC series broadband directional couplers are multi-hole waveguide couplers. The QDC series couplers are offered in 7 waveguide sizes from 18.0 to 110 GHz. Nominal coupling of 10 dB, 20 dB, 30 dB, and 40 dB are offered as standard products. Two different mechanical configurations or outlines are offered for these waveguide couplers- one with E-plane bend and the other with H-plane bend in the coupled port to suit the physical layout of all applications or test set requirements.QuinStar also offers Series QJG and QJR Precision Directional Couplers in rectangular block geometry.