3-11 GHz Monolithic Balun in CMOS Technology for UWB Applications

In this paper, a 3-11 GHz monolithic balun for ultra- wide-band (UWB) applications is proposed. Implemented in TSMC´s one-poly eight-metal (1P8M) 0.13 mum mixed-signal (MS)/RF CMOS process, it exhibits a good performance from 3 to 11 GHz. The insertion loss is <1.4 dB over the whole UWB band. The symmetry is perfect. The absolute magnitude imbalance is <0.02 dB and the absolute phase imbalance is <0.2deg. The return loss of single-ended port can be <-10 dB when a simple capacitor tuning technique is employed.