Design of a broadband directional coupler using microstrip-like multilayertechnology

An improved 3 dB broadband double-sided slot-coupled directional coupler ha s been designed and implemented. The slot is modified by trimming the sharp rectangular edges and the coupled microstrip lines in the coupling region. The performance of the coupler shows good agreement with the simulated fre quency response. The main improvement is in the significant reduction of ri pple amplitude in the design bandwidth. Insertion loss of the novel coupler has also been reduced compared to the conventional rectangular slot couple r. (C) 1999 John Wiley & Sons, Inc.