Broadband and high-K passive balun using 16 sides geometry for silicon-based RFICs

A broadband and high-<;i>K<;/i> monolithic passive balun for silicon-based radio frequency integrated circuits (RFICs) are presented. It utilises the top level thick Cu metal and adopts a 16-side geometry. The proposed balun is designed and fabricated with a 0.13-μm CMOS mixed-signal 1P6M process. The measured results show that the amplitude imbalance is <; 0.2 dB and the phase imbalance is within 4° from the frequency range of 0.1-7 GHz. Compared with the typical octagonal balun, the proposed design achieves the same coupling coefficients <;i>K<;/i> and attains an enhancement in the transmission efficiency <;i>S<;/i><;sub>21<;/sub> within the frequency range of 0.1-20 GHz, and the consumed chip area is reduced by 3%.