Abstract
This work presents an ultra-wideband (UWB) active balun (balanced-to-unbalanced) with current-reused technique for wideband input matching and low power consumption by using standard 0.18 μm CMOS processes. The proposed circuit, using parallel common gate and common source structure, can efficiently improve the input-matching bandwidth for up to 10 GHz. Besides, the proposed circuit has good gain imbalance and phase imbalance from 3.1 GHz to 10.6 GHz. The proposed active balun achieved 4 ± 1 dB gain with amplitude (gain) imbalances less than 0.5 dB, phase differences of 180° ± 2°, 11.7 mW power consumption at 1.8 V supply voltage from 3.1 GHz to 10.6 GHz, and the chip size including pads is 0.76 × 0.73 mm2.