This paper presents the design of wideband directional coupler with enhanced isolation performance. Studies show that introducing the zigzag coupling releases the phase-velocity difference between the even-and odd-mode in the coupling region, thus improving the directivity. To further improve the performance, wedge structure is proposed, and therefore, a wideband coupled-line directional coupler is developed with enhanced isolation responses. The presented coupler characterizes simple architecture, planar layout, symmetric topology, symmetric coupling and isolation responses that are the basic differ-