Characteristics of $0-\Omega$ Transmission Lines for Millimeter-Wave Circuits in $0.18\ \mu \mathrm{m}$ CMOS Technology

A 0-Ω transmission line ( 0-Ω TL) has been proposed as a decoupling capacitor in a high frequency band. 0-Ω TL is configured by combining three types of capacitors which are metal-insulator-metal (MIM) capacitors, metal-oxide-metal (MOM) capacitors, and MOS capacitors. By large capacitance of those capacitors, a 0-Ω TL has very low characteristic impedance. The optimum configuration of a 0-Ω TL in a 1P5M 0.18 μm CMOS technology was reported to be the configuration of MOM capacitors and MOS capacitors. However, it has not been evaluated by measurement. In this paper, the optimal configuration of 0-Ω TL is clarified by measurement. Moreover, we show that the variation of gate biases of MOS capacitors does not significantly affect the characteristics of a 0-Ω TL.