An L-Band Loop-Type Coupler (Correspondence)

The design of loop couplers for various loop length has been reported by Lombardini, Schwartz and Kelly. This device is useful for many applications as the over-all length can be held to about 6 inches, whereas a com-parable multihole coupler must be on the order of several feet long. The loop-type device couples a TE₁₀ waveguide mode from a RG-69/U to a TEM mode in a 3/8-inch coaxial line. A comb-type coupler, for coupling a coaxial line to TE_I0 waveguide, was reported by Lombardini and Schwartz. This device made use of a multiple-capacitive probe situated in a longitudinal slot in the top wall of the waveguide.