A Mix-Mode Hybrid Using Broadside-Coupled Asymmetric Coplanar Striplines

In this paper, a mix-mode hybrid coupler based on broadside-coupled asymmetric coplanar striplines (ACPSs) is proposed. The major advantages of this coupler are its broadband characteristic and impedance transforming property. While providing a simple design procedure for the coupler, analytical details are also discussed. A prototype operating between 3–6 GHz for differential-mode and 0–3 GHz for common-mode has been designed and fabricated using the conventional printed-circuit board (PCB) technology. Measured results are in good agreement with those obtained from full-wave simulations, showing a promising potential of the proposed mix-mode hybrid for a variety of applications.