Low-loss Balun Design and Compact Modeling for RF/Millimeter-Wave Circuit Application

On-chip baluns are widely used in RF and Millimeter-Wave circuit. How to reduce the insertion loss is the key issue for balun designs. Meanwhile, an accurate compact model for balun is highly demanded. In this work, the Patterned Ground Shields and Parallel Metal Layer techniques are used to reduce the insertion loss of the balun. The compact model and corresponding extraction techniques are also presented. Experimental results show that the insertion loss of the fabricated balun is about 1.4db and the proposed compact model can describe it up to 30GHz accurately.