摘要: A directional coupler includes a primary transmission line electrically coupled in series between an input port and an output port of the coupler, and an asymmetric, meander-shaped, secondary transmission line, which is electrically coupled in series between a coupling port and an isolation port of the coupler. The secondary transmission line includes a first coupling segment, which is reactively coupled to a first portion of the primary transmission line, and a second coupling segment, which is reactively coupled to a second portion of the primary transmission line, and is spaced closer to, or farther from, the primary transmission line relative to the first coupling segment, such that an asymmetry in reactive coupling is present between the first and second portions of the primary transmission line and the secondary transmission line. An intermediate segment is provided, which is electrically coupled in series between the …