A fully planar microstrip coupled-line coupler with a high coupling level

Abstract

A fully planar microstrip coupler with a high coupling level tip to 4 dB is fabricated on PCB. Based on the conventional coupled-line structure, a gap Size of coupled lines about 14 mu m is realized by low cost IC process. It has a single stage and requires no bond wire. In measurement, a bandwidth more than 50% and isolation and return loss better than -20 dB are achieved. The measured responses have good agreement with EM simulation data. (c) 2005 Wiley Periodicals, Inc.