Design of CMOS On-Chip Millimeter-Wave Transformer Coupled Balun and Power Divider-Combiner with Optimal Amplitude and Phase Imbalance

Abstract

Millimeter-wave passive elements are one of the vital part to distribute power through integrated circuitry. And transformer coupled passive devices are used not only for signal transmitting but also making chip area smaller. A transformer coupled planar and stacked type both could be used for balun and power divider-combiner design. This type of balun provide small amplitude imbalance ~2dB and 180° phase imbalance between 57-120 GHz bandwidth (BW) and successively shrinking the layout area of 0.0061mm2. On the other hand, transformer coupled two way power divider-combiner (PD-C) occupies 0.0088 mm2 (7.5 Times Smaller than Wilkinson PD-C) with amplitude variation ~1.87dB and phase angle variation 3° with larger BW (50-120 GHz). Again four way PD-C occupies 0.0122mm2 (5 Times Smaller than Wilkinson PD-C) having amplitude variation ~2dB and phase angle variation 2.8° with a larger BW 50-120 GHz. Proposed stacked small transformers with a center trapped baluns and power divider-combiner have been implied on two millimetre-wave amplifiers on 55nm DDC CMOS.